无法推送到 GitHub - 一直说需要合并

Pushing to git@github.com:519ebayproject/519ebayproject.git
To git@github.com:519ebayproject/519ebayproject.git
 ! [rejected]        master -> master (non-fast-forward)
error: failed to push some refs to 'git@github.com:519ebayproject/519ebayproject.git'
hint: Updates were rejected because the tip of your current branch is behind
hint: its remote counterpart. Merge the remote changes (e.g. 'git pull')
hint: before pushing again.
hint: See the 'Note about fast-forwards' in 'git push --help' for details.

答案