[Fixed] git push rejected (non-fast forward)

下git push時遇到被reject的錯誤

$ git push origin master
To git@github.com:${USR}/mvn-repo.git
 ! [rejected]        master -> master (non-fast-forward)
error: failed to push some refs to 'git@github.com:${USR}/mvn-repo.git'
To prevent you from losing history, non-fast-forward updates were rejected
Merge the remote changes (e.g. 'git pull') before pushing again.  See the
'Note about fast-forwards' section of 'git push --help' for details.

只要先下git pull，在下git push就會正常了

$ git pull origin master
$ git push origin master

Reference: rip747