Add documentation re :validatable

lib/generators/devise/twitter_generator.rb

@@ -13,13 +13,27 @@ def inject_devise_twitter_intomodel
   # To use devise-twitter don't forget to include the :twitter_oauth module:
   # e.g. devise :database_authenticatable, ... , :twitter_oauth
 
+  # IMPORTANT: If you want to support sign in via twitter you MUST remove the
+  #            :validatable module, otherwise the user will never be saved
+  #            since it's email and password is blank.
+  #            :validatable checks only email and password so it's safe to remove
+
 CONTENT
       end
 
       def copy_initializer
         template "initializer.rb", "config/initializers/devise_twitter.rb"
       end
 
+      def add_devise_twitter_routes
+        route <<-CONTENT
+devise_for :#{singular_name} do
+    match '/#{singular_name}/sign_in/twitter' => Devise::Twitter::Rack::Signin
+    match '/#{singular_name}/connect/twitter' => Devise::Twitter::Rack::Connect
+  end
+CONTENT
+      end
+
       def show_readme
         readme "README" if behavior == :invoke
       end