github 오류 보고 failed to push some refs to'git

$ git push origin master
Warning: Permanently added the RSA host key for IP address '192.30.253.112' to the list of known hosts.
To [email protected]:Tuesdday/pythoncode.git
 ! [rejected]        master -> master (fetch first)
error: failed to push some refs to '[email protected]:Tuesdday/pythoncode.git'
# 
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.

문제의 원인:

해결 방법:

$ git pull --rebase origin master  # 。
warning: no common commits
remote: Counting objects: 3, done.
remote: Total 3 (delta 0), reused 0 (delta 0), pack-reused 0
Unpacking objects: 100% (3/3), done.
From github.com:Tuesdday/pythoncode
 * branch            master     -> FETCH_HEAD
 * [new branch]      master     -> origin/master
First, rewinding head to replay your work on top of it...
Applying: practice

결과:

 git push -u origin master
Counting objects: 15, done.
Delta compression using up to 4 threads.
Compressing objects: 100% (13/13), done.
Writing objects: 100% (15/15), 3.27 KiB | 0 bytes/s, done.
Total 15 (delta 1), reused 0 (delta 0)
To git@github.com:Tuesdday/pythoncode.git
   28bae99..eb67c9a  master -> master
Branch master set up to track remote branch master from origin.