error: failed to push some refs to 'XXXX'
hint: Updates were rejected because the remote contains work that you do
hint: not have locally. This is usually caused by another repository pushing
hint: to the same ref. You may want to first integrate the remote changes
hint: (e.g., 'git pull ...') before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.
大概意思是: 本地和远程的文件应该合并后才能上传本地的新文件;
解决方法：
1、先拉下来，将两个仓库内容合并
git pull --rebase origin master
2、再上传
git push -u origin master
亲测有效。