public function addEnumValue ($table, $column, $value, $default = false)
		{
			echo "    > add enum value $value to column $column in $table ...\n";
			$time = microtime(true);

			$columnSchema = $this->db->getTableSchema($table)->columns[ $column ];
			$values = $columnSchema->enumValues;
			$values[] = $value;
			$defaultValue = $default ? $value : $columnSchema->defaultValue;
			$this->alterColumn($table, $column, $this->enum($values)->defaultValue($defaultValue));

			echo '    > done (time: ' . sprintf('%.3f', microtime(true) - $time) . "s)\n";
		}