add details for ssh key settings

README.md

@@ -35,8 +35,10 @@ git clone https://git.wikipali.org/iapt-platform/tutorial.git
   ```
 
 - 把`.ssh/id_rsa.pub`内容添加到你的账户
-  ![step 1](images/git/add-keys/1.png)
-  ![step 2](images/git/add-keys/2.png)
+  - 打开配置页面
+    ![step 1](images/git/add-keys/1.png)
+  - 添加ssh key
+    ![step 2](images/git/add-keys/2.png)
 - 克隆项目
 
   ```bash