In my rails application I once used authlogic-oid and ruby-openid. Now I want to get rid of them and I removed both gems and also their config.gem lines from my environment.rb.
Although my application works, I can't do any database migrations because I get a "Missing these required gems" error. Also if I run rake gems:install these gems are re-installed.
Where are the references to the gems stored?
The standard way to define a gem dependency is in the environment configuration. It usually takes place in the environment.rb file for any environment, but some gems might be specified also per-environment. Check the environment files in config/environments.
Also make sure some file doesn't include the gem with the classic RubyGems gem command.
Finally, check these gems are not required by other gems or plugins used by your application.