Description:
  Stubs out a enumeration module. Pass the enumeration name, either CamelCased or
  under_scored, and an optional list of member value pairs as arguments.
  "Enum" will be appended to the name of the module.

  Member pairs are member:value arguments specifying the members and optionally their values.
  If the value part is omitted, an integer value will be assigned, based on the members position
  in the list of member arguments

  You don't have to think up every member up front, but it helps to
  sketch out a few so you can start working with the enumeration immediately.

  This generator invokes your configured test framework which defaults to TestUnit

  If you pass a namespaced enumeration name (e.g. admin/account_type or Admin::AccountType)
  then the generator will create a module (e.g. admin_account_type)

Examples:
  `rails generate riveter:enum account_type`

    Creates an enumeration module

      Enum: app/enums/account_type_enum.rb

  `rails generate riveter:enum admin/account_type`

    Creates an enumeration module within the admin namespace

      Enum: app/enums/admin/account_type_enum.rb

  `rails generate riveter:enum account_type local foreign`

    Creates an enumeration module, with "Local" and "Foreign" as members with default integer values

      Enum: app/enums/account_type_enum.rb

  `rails generate riveter:enum account_type local:1 foreign:2`

    Creates an enumeration module, with "Local" and "Foreign" as members with the values 1 and 2 respectively

      Enum: app/enums/account_type_enum.rb