added support for database expressions.

laravel/database/manager.php

@@ -91,6 +91,19 @@ class Manager {
 		return static::connection($connection)->table($table);
 	}
 
+	/**
+	 * Create a new database expression instance.
+	 *
+	 * Database expressions are used to inject raw SQL into a fluent query.
+	 *
+	 * @param  string      $value
+	 * @return Expression
+	 */
+	public static function raw($value)
+	{
+		return new Expression($value);
+	}
+
 	/**
 	 * Magic Method for calling methods on the default database connection.
 	 *