Add DateTime support to database binding layer.

Signed-off-by: Taylor Otwell <taylorotwell@gmail.com>

laravel/database/query/grammars/sqlserver.php

@@ -11,6 +11,13 @@ class SQLServer extends Grammar {
 	 */
 	protected $wrapper = '[%s]';
 
+	/**
+	 * The format for properly saving a DateTime.
+	 *
+	 * @var string
+	 */
+	public $datetime = 'Y-m-d H:i:s.000';
+
 	/**
 	 * Compile a SQL SELECT statement from a Query instance.
 	 *