Ruby on rails Heroku部署错误无法创建产品

我尝试在Heroku应用程序本身上创建一个产品。但我在上传产品后意识到。我猜100%之后，当它尝试创建新产品时，页面会向我显示错误消息，我们很抱歉，但出现了一些问题

应用程序在heroku上，链接是

Web应用程序：

假帐户电子邮件地址：hello@hello.com

密码：密码

我该怎么处理呢

顺便说一下，我正在使用carrierwave上传照片。谢谢大家!

2015-05-07T08:23:41.093033+00:00 heroku[router]: at=info method=GET path="/products/new" host=sleepy-ridge-5350.herokuapp.com request_id=e0c640ec-2436-4d91-8041-dcb463d6f249 fwd="183.171.162.179" dyno=web.1 connect=0ms service=15ms status=200 bytes=4010
2015-05-07T08:23:41.085768+00:00 app[web.1]:   Rendered products/_form.html.erb (3.3ms)
2015-05-07T08:23:41.078314+00:00 app[web.1]: Processing by ProductsController#new as HTML
2015-05-07T08:23:41.087132+00:00 app[web.1]: Completed 200 OK in 9ms (Views: 5.1ms | ActiveRecord: 1.2ms)
2015-05-07T08:23:41.075985+00:00 app[web.1]: Started GET "/products/new" for 183.171.162.179 at 2015-05-07 08:23:41 +0000
2015-05-07T08:23:41.081123+00:00 app[web.1]:   User Load (1.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" ASC LIMIT 1  [["id", 2]]
2015-05-07T08:23:41.703898+00:00 heroku[router]: at=info method=GET path="/assets/application-57e4f4df63b3b53b7b9e71997c86f25266f0c866c128a2dc6418dd6ffc4577e6.css" host=sleepy-ridge-5350.herokuapp.com request_id=9d980949-9955-4ab0-bf50-ad2830bf5acf fwd="183.171.162.179" dyno=web.1 connect=0ms service=3ms status=304 bytes=133
2015-05-07T08:23:42.765147+00:00 heroku[router]: at=info method=GET path="/favicon.ico" host=sleepy-ridge-5350.herokuapp.com request_id=4da30674-4b92-4d28-8ce3-1d13039cd499 fwd="183.171.162.179" dyno=web.1 connect=2ms service=6ms status=304 bytes=133
2015-05-07T08:23:52.126665+00:00 app[web.1]: Started POST "/products" for 183.171.162.179 at 2015-05-07 08:23:52 +0000
2015-05-07T08:23:52.132125+00:00 app[web.1]:   Parameters: {"utf8"=>"✓", "authenticity_token"=>"ZZ/LeoAQ6bLF4MYLjIRVNe+vB1avsG9iD3Ws0U4Dv08zYCtafly2Xg/zrQgvDED/Y0vsoymYD5SDSnfTfhW7nQ==", "product"=>{"name"=>"Bear", "description"=>"bear", "price"=>"12", "file"=>#<ActionDispatch::Http::UploadedFile:0x007fb2d0104700 @tempfile=#<Tempfile:/tmp/RackMultipart20150507-3-bm2rc7.jpg>, @original_filename="bear.jpg", @content_type="image/jpeg", @headers="Content-Disposition: form-data; name=\"product[file]\"; filename=\"bear.jpg\"\r\nContent-Type: image/jpeg\r\n">}, "commit"=>"Create Product"}
2015-05-07T08:23:52.129909+00:00 app[web.1]: Processing by ProductsController#create as HTML
2015-05-07T08:23:52.135307+00:00 app[web.1]:   User Load (1.2ms)  SELECT  "users".* FROM "users" WHERE "users"."id" = $1  ORDER BY "users"."id" ASC LIMIT 1  [["id", 2]]
2015-05-07T08:23:52.910182+00:00 heroku[router]: at=info method=POST path="/products" host=sleepy-ridge-5350.herokuapp.com request_id=23119ad8-3f67-47d7-a6ae-c23188df9d70 fwd="183.171.162.179" dyno=web.1 connect=30ms service=1257ms status=500 bytes=1754
2015-05-07T08:23:52.877912+00:00 app[web.1]: Completed 500 Internal Server Error in 745ms
2015-05-07T08:23:52.879793+00:00 app[web.1]: NoMethodError (undefined method `val' for #<Arel::Nodes::BindParam:0x007fb2d0111ba8>):
2015-05-07T08:23:52.879798+00:00 app[web.1]: 
2015-05-07T08:23:52.879795+00:00 app[web.1]:   app/controllers/products_controller.rb:27:in `create'
2015-05-07T08:23:52.879790+00:00 app[web.1]: 

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你可以查看heroku的日志，然后可以看到它的崩溃之处，我已经更新了日志。请帮我分析一下，因为我对rails还很陌生。