refactoring for dependency injection and testability.

laravel/database/query/compiler/mysql.php

@@ -0,0 +1,14 @@
+<?php namespace Laravel\Database\Query\Compiler;
+
+use Laravel\Database\Query\Compiler;
+
+class MySQL extends Compiler {
+
+	/**
+	 * Get the keyword identifier wrapper for the connection.
+	 *
+	 * @return string
+	 */
+	public function wrapper() { return '`'; }
+
+}