AR migration generator includes model's modules in table name. [#4230]

Hello! Could someone review the patch attached to [1] and provide feedback?

Briefly, it targets rails 3, and fixes "rails g model admin/post". The generated migration creates a "admin_posts" table while the model expects a table simply named "posts". With the patch, the migration creates "posts".

Thank you!   --phil--

[1] #4230 [PATCH] AR migration generator includes model's modules in table name. - Ruby on Rails - rails

I've added two alternative patches. The 2nd is a variation on the first that avoids introducing a new method in NamedBase. The 3rd leaves NamedBase completely alone, and instead adds 'self.table_name_prefix = "admin_"' to generated models.