Update README.md

applications/Demo/README.md

@@ -104,7 +104,7 @@ class Db
     );
   
     // 数据库实例2
-    public static $db2 = array array(
+    public static $db2 = array(
         'host'    => '127.0.0.1',
         'port'    => 3306,
         'user'    => 'mysql_user',
@@ -173,4 +173,4 @@ $row_count = $db1->delete('Persons')->where('ID=9')->query();
 // 等价于
 $row_count = $db1->query("DELETE FROM `Persons` WHERE ID=9");
 
-```
+```