等待命运之剑
--------------------------------
|---github----------------------------|
|               ①fork                |
|liao/learngit ------> amtree/leargit |
|              <------      ↑  |      |
|          ⑤pull request   |  |      |
|___________________________|__|______|
                            |  |
                     ④push |  | ②clone
                            |  ↓
                          local/leargit
                       ③ur file、add、commit