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.