Change the cookie secret token at config/initializers/secret_token.rb

Create a config/initializers/secret_token.rb file:

That will rename your app in the following files: ... config/initializers/secret_token.rb

Change your Application’s Secret Token ...

Change the secret token at /config/initializers/secret_token.rb

Those are the first six items in order and the trend continues at least through the first page of results.