Added documentation for model migration generation

activerecord/lib/rails/generators/active_record/model/model_generator.rb

@@ -12,6 +12,9 @@ class ModelGenerator < Base # :nodoc:
       class_option :parent,     :type => :string, :desc => "The parent class for the generated model"
       class_option :indexes,    :type => :boolean, :default => true, :desc => "Add indexes for references and belongs_to columns"
 
+
+      # creates the migration file for the model first followed by the model file itself
+
       def create_migration_file
         return unless options[:migration] && options[:parent].nil?
         attributes.each { |a| a.attr_options.delete(:index) if a.reference? && !a.has_index? } if options[:indexes] == false
@@ -39,6 +42,7 @@ def accessible_attributes
 
       protected
 
+        # Used by the migration template to determine the parent name of the model
         def parent_class_name
           options[:parent] || "ActiveRecord::Base"
         end