Description:

The `rails plugin new` command creates a Rails plugin with the ability
to run tests using a dummy Rails application. A plugin is a gem with
either a railtie or an engine.

Examples:

`rails plugin new ~/Code/Ruby/blog`

This generates a Rails railtie gem in ~/Code/Ruby/blog.
See the README in the newly created plugin to get going.

`rails plugin new blog --full`

This generates a full Rails engine gem in ./blog. The `--mountable`
option may also be used to generate a mountable, namespace-isolated
engine with assets and layouts.

`rails plugin new blog --mountable --skip-asset-pipeline`

This generates a mountable Rails engine gem at ./blog without an asset
pipeline. Any part of Rails can be skipped during plugin generation.