Ruby on rails 回形针2.6.0被中止！单位化常数AddAvatarColumnsToUser错误

我正在按照安装回形针的步骤进行操作，并在尝试迁移数据库时出错。我已经包括了下面终端的错误。我正在使用MacOSX。我认为这与Imagemagick有关，但不确定。我有回形针2.6.0和Rails 3.2.0。如果有人知道答案，我将不胜感激，因为经过数小时的搜索，我还没有找到答案

    Timothy-Muellers-MacBook-Pro:Publishr tmuelle1$ rake db:migrate --trace
    ** Invoke db:migrate (first_time)
    ** Invoke environment (first_time)
    ** Execute environment
    ** Invoke db:load_config (first_time)
    ** Invoke rails_env (first_time)
    ** Execute rails_env
    ** Execute db:load_config
    ** Execute db:migrate
    rake aborted!
    An error has occurred, this and all later migrations canceled:

    uninitialized constant AddAvatarColumnsToUsers
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_support/inflector/methods.rb:226:in `block in constantize'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_support/inflector/methods.rb:225:in `each'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_support/inflector/methods.rb:225:in `constantize'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_support/core_ext/string/inflections.rb:54:in `constantize'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:521:in `load_migration'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:516:in `migration'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:511:in `migrate'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:696:in `block (2 levels) in migrate'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in `call'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in `block in ddl_transaction'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/connection_adapters/abstract/database_statements.rb:190:in `transaction'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/transactions.rb:208:in `transaction'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in `ddl_transaction'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:695:in `block in migrate'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:676:in `each'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:676:in `migrate'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:553:in `up'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:534:in `migrate'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/railties/databases.rake:152:in `block (2 levels) in <top (required)>'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `call'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:205:in `block in execute'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `each'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:200:in `execute'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:158:in `block in invoke_with_call_chain'
    /Users/tmuelle1/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/monitor.rb:201:in `mon_synchronize'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:151:in `invoke_with_call_chain'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:144:in `invoke'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:116:in `invoke_task'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block (2 levels) in top_level'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `each'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `block in top_level'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:88:in `top_level'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:66:in `block in run'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:in `standard_exception_handling'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:63:in `run'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/bin/rake:33:in `<top (required)>'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/bin/rake:19:in `load'
    /Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/bin/rake:19:in `<main>'
    Tasks: TOP => db:migrate

Timothy Muellers MacBook Pro:Publisher tmuelle1$rake db:migrate--trace
**调用数据库：迁移（第一次）
**调用环境（第一次）
**执行环境
**调用数据库：加载配置（第一次）
**调用rails_env（第一次）
**执行rails_env
**执行db:load\u config
**执行数据库：迁移
雷克流产了！
发生错误，此迁移和所有后续迁移已取消：
未初始化常量AddAvatarColumnsToUsers
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_-support/definctor/methods.rb:226:in'block in constantize'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_-support/endictor/methods.rb:225:in'each'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active_-support/endoctor/methods.rb:225:in'constantize'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activesupport-3.2.0.rc1/lib/active\u support/core\u ext/string/definctions.rb:54:in'constantize'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active\u record/migration.rb:521:in'load\u migration'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:516:in'migration'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:511:in'migrate'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:696:in“migrate中的块（2个级别）”中
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in'call'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in`block in ddl_transaction'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active\u record/connection\u adapters/abstract/database\u statements.rb:190:in'transaction'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/transactions.rb:208:in'transaction'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:751:in'ddl_transaction'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:695:in'block in migrate'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:676:in'each'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:676:in'migrate'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:553:in'up'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/migration.rb:534:in'migrate'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/activerecord-3.2.0.rc1/lib/active_record/railties/databases.rake:152:in'block（2层）in'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:205:in'call'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:205:in'block in execute'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:200:in'each'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:200:in'execute'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:158:in'block in invoke_with_call_chain'
/Users/tmuelle1/.rvm/rubies/ruby-1.9.2-head/lib/ruby/1.9.1/monitor.rb:201:in'mon_synchronize'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:151:in'invoke_with_call_chain'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/task.rb:144:in'invoke'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:116:in'invoke_task'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in `顶层的块（2层）'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in'each'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:94:in“顶层块”
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:在“标准异常处理”中
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:88:“顶级”
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:66:in'block in run'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:133:在“标准异常处理”中
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/lib/rake/application.rb:63:in'run'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/gems/rake-0.9.2.2/bin/rake:33:in`'
/Users/tmuelle1/.rvm/gems/ruby-1.9.2-head@rails3tutorial/垃圾桶/耙子：19:i
class AddAvatarColumnsToUser < ActiveRecord::Migration 

class AddAvatarColumnsToUsers < ActiveRecord::Migration