To git@gitlab.crans.org:******/Demo.git
 ! [rejected]        master -> master (non-fast-forward)
 error: failed to push some refs to 'git@gitlab.crans.org:******/Demo.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.
