//Team.php
class Team extends Page {

	private static $has_one = array(
		'TeamTypes' => 'TeamType'
	);


   // Additional Tab to add additional Team Types
	   $fields->addFieldToTab('Root.TeamTypes', GridField::create(
	   		'TeamTypesID',
	   		'Team categories',
	   		$this->TeamTypes(),
	   		GridFieldConfig_RecordEditor::create()
	   ));

	   // Dropdown options
	   $field = DropdownField::create(
	   				'TeamTypesID', //Name of has one relationship
	   				'Team Category',  //Title or Label
	   				TeamType::get()->map('ID', 'Title')) //Source
	   		    ->setEmptyString('(Select one)'); //Add an empty string

	   $fields->addFieldToTab('Root.Main', $field, 'Content');
	   $fields->addFieldToTab('Root.Main', TextField::create('Website'), 'Content');

	   return $fields;
	}
}

//TeamType
class TeamType extends DataObject {
	private static $db = array(
		'Title' 		=> 'Varchar'
	);

	private static $has_many = array(
		'Teams' => 'Team'
	);

}