Find where your ruby method been defined at.
1.9.2p290 :003 > User.method(:all).source_location
=> ["/Users/michaelhe/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/base.rb", 443]
1.9.2p290 :003 > User.method(:all).source_location
=> ["/Users/michaelhe/.rvm/gems/ruby-1.9.2-p290/gems/activerecord-3.0.11/lib/active_record/base.rb", 443]