Ruby on rails 通过表单向表中添加行

我正在尝试创建一个表单，该表单将向我的表中添加一行，但我遇到此错误，我不确定原因：

Started POST "/test" for ::1 at 2014-11-30 01:51:49 -0800
Processing by UsersController#create as JS
  Parameters: {"utf8"=>"✓", "users"=>{"first_name"=>"brady", "last_name"=>"LIII", "email"=>"brad@gmail.com", "phone_number"=>"123456789"}, "commit"=>"Save Users"}
Completed 500 Internal Server Error in 1ms

NoMethodError (undefined method `[]' for nil:NilClass):
  app/controllers/users_controller.rb:32:in `create'


  Rendered /Users/bli1/.rvm/gems/ruby-2.1.3/gems/web-console-2.0.0.beta4/lib/action_dispatch/templates/rescues/_source.erb (2.0ms)
  Rendered /Users/bli1/.rvm/gems/ruby-2.1.3/gems/web-console-2.0.0.beta4/lib/action_dispatch/templates/rescues/_trace.text.erb (0.9ms)
  Rendered /Users/bli1/.rvm/gems/ruby-2.1.3/gems/web-console-2.0.0.beta4/lib/action_dispatch/templates/rescues/_request_and_response.text.erb (0.5ms)
  Rendered /Users/bli1/.rvm/gems/ruby-2.1.3/gems/web-console-2.0.0.beta4/lib/action_dispatch/templates/rescues/diagnostics.text.erb (11.5ms)
::1 - - [30/Nov/2014:01:51:49 -0800] "POST /test HTTP/1.1" 500 92618 0.0449

我的表格：

<!-- contact -->
<section id="contact">
  <div class="container">
    <div class="title-container">Contact Us</div>
    <div class="title-caption">Reach us at (415)-911-9999</div>
    <%= form_for(:users, remote: true, id: "contact-form", class: "contact-input") do |f| %>
      <div class="col-md-12">
        <div class="col-md-6">
          <div class="contact-input-margin form-group">
            <%= f.text_field(:first_name, class: "form-control", placeholder: "First name")%>
          </div>
          <div class="contact-input-margin form-group">
            <%= f.text_field(:last_name, class: "form-control", placeholder: "Last name") %>
          </div>
          <div class="contact-input-margin form-group">
            <%= f.email_field(:email, class: "form-control", placeholder: "Email") %>
          </div>
          <div class="contact-input-margin form-group">
            <%= f.telephone_field(:phone_number, class: "form-control", placeholder: "Phone number") %>
          </div>
        </div>
      </div>
      <%= f.submit(class: "btn btn-xl") %>
    <% end %>
  </div>
</section>

模式：

ActiveRecord::Schema.define(version: 20141130075753) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "contact_requests", force: true do |t|
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.text     "message",    null: false
    t.integer  "user_id"
  end

  add_index "contact_requests", ["user_id"], name: "index_contact_requests_on_user_id", using: :btree

  create_table "users", force: true do |t|
    t.datetime "created_at",   null: false
    t.datetime "updated_at",   null: false
    t.string   "first_name",   null: false
    t.string   "last_name",    null: false
    t.string   "email",        null: false
    t.string   "phone_number"
  end

end

它必须是params[：users]，如上所述，User.find_byemail:params[：User][：email]应该有：users，而不仅仅是：User。

class User < ActiveRecord::Base
  before_save { |user| user.email = user.email.downcase }
  has_many :contact_requests
  validates(:first_name, presence: true)
  validates(:last_name, presence: true)
  validates(:email, presence: true)
  accepts_nested_attributes_for :contact_requests
end

Rails.application.routes.draw do
  root 'home#index'
  get 'test', to: "users#new"
  post 'test', to: "users#create"

ActiveRecord::Schema.define(version: 20141130075753) do

  # These are extensions that must be enabled in order to support this database
  enable_extension "plpgsql"

  create_table "contact_requests", force: true do |t|
    t.datetime "created_at", null: false
    t.datetime "updated_at", null: false
    t.text     "message",    null: false
    t.integer  "user_id"
  end

  add_index "contact_requests", ["user_id"], name: "index_contact_requests_on_user_id", using: :btree

  create_table "users", force: true do |t|
    t.datetime "created_at",   null: false
    t.datetime "updated_at",   null: false
    t.string   "first_name",   null: false
    t.string   "last_name",    null: false
    t.string   "email",        null: false
    t.string   "phone_number"
  end

end