Tclone
Just copy the templates of the rails generators to the your rails project.
Installation
Configure the Gemfile:
gem 'tclone'
Usage
To copy the templates used by the scaffold generator:
rails g tclone scaffold
# Above command will copy all the templates used by the scaffold generator to your rails project( RAILS_ROOT/lib/templates/ )
Now, you can modify the template used by the scaffole generator.