Updates the installation generator to handle DB migrations

* Fixes the 'c_a_sino' module inflection issue with Thor
* Moves the generator to its own directory so that it can co-exist with
  future generators
* Adds a '--skip-migration' CLI option
* Fixes an improper engine mount location.

  The `:as` option specifies the namespace for an Engine's named routes.
  By default, this is the same as the Engine's `engine_name` property.
  In the case of CASino, this would equal `casino_engine`, which is the
  "down cased" string value of `CASino::Engine`

  In order to keep this both simple and consistent, the `:as` attribute
  should be in lowercase. Otherwise, the namespace would look like a
  constant which would be inaccurate.
Install CASino into the dummy test application
database.yml is not our business