a little change of reademe

README.md

@@ -60,6 +60,7 @@ rows, err := engine.Update(&user)
 ```
 
 3.Fetch a single object by user
+
 ```go
 var user = User{Id:27}
 engine.Get(&user)
@@ -79,6 +80,7 @@ if err != nil {
 ```
 
 1.Fetch a single object by where
+
 ```go
 var user Userinfo
 session.Where("id=?", 27).Get(&user)