Description:
    Creates a database.yml file and a rails initializer for use with MongoMapper.

Examples:
    `./script/generate mongo_initializer`

        creates an initializer:
            Initializer:      config/initializers/mongomapper.rb
			Config:			  config/database.yml
			

    `./script/generate mongo_initializer databasename`

		generates the same files as above, and uses the databasename in the config file.