Description:
    Invokes the active_record:model generator, but the generated
    model file contains the fields block, (and the migration option
    is false by default).

Examples:
    $ rails generate declare_schema:model account

        creates an Account model, test and fixture:
            Model:      app/models/account.rb
            Test:       test/unit/account_test.rb
            Fixtures:   test/fixtures/accounts.yml

    $ rails generate declare_schema:model post title:string body:text published:boolean

        creates a Post model with a string title, text body, and published flag.

After the model is created, and the fields are specified, use declare_schema:migration
to create the migrations incrementally.