Description:
    Stubs out a new model. Pass the model name, either CamelCased or
    under_scored, and an optional list of attribute pairs as arguments.

    Attribute pairs are key_name:mongo_type arguments specifying the
    model's attributes. Timestamps and Userstamps are added by default.

Examples:
    `./script/generate embedded_model account`

        creates an Account model:
            Model:      app/models/account.rb

    `./script/generate embedded_model post title:string body:string published:boolean`

        creates a Post model with a string title, string body, published flag, timestamps! and userstamps!.

    `./script/generate embedded_model post --skip-timestamps`

        creates a Post model with no timestamps.

    `./script/generate embedded_model post --skip-userstamps`

        creates a Post model with no userstamps.