Rails NoMethod Error when calling a dynamic attribute find

I am currently working on an app. In this app, I created a Person model and I was using rail's dynamic attribute find feature. In the Person model I have an attribute called uid, so I was calling Person.find_by_uid(some numerical value). This worked fine in my development mode and the app was totally functioning. However, once I deployed this app to heroku. The app failed and the log complains about NoMethodError (undefined method `find_by_uid' for #):

I have been looking all places, but still unable to track down the problem. I tried to define the method find_by_uid under the Person model, and still does not work.

I was wonde开发者_高级运维ring if anyone has had similar experience or knows how to solve this issue?

Thank you very much ahead of the time!

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Did you try running the migrations in heroku (heroku rake db:migrate)? Most provably that attribute is not in the heroku data base so you don't have that dynamic method.

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I ran into the same problem. heroku restart has saved me.