ssh-keygen -t rsa -C "your_email@example.com"
cat ~/.ssh/id_rsa.pub

Copy the content in the SSH keys of your Github profile
Test:

 ssh -T git@github.com

in your local copy of the repository:

git remote set-url origin git@github.com:username/your-repository.git

Then once you changed something

git commit -am "your comment"
git push

git config merge.tool vimdiff
git config merge.conflictstyle diff3
git config mergetool.prompt false

Navigate using Ctl+W between LOcal BAse REmote
or MErge windows displayed like so:

╔═══════╦══════╦════════╗
║       ║      ║        ║
║ LOCAL ║ BASE ║ REMOTE ║
║       ║      ║        ║
╠═══════╩══════╩════════╣
║                       ║
║        MERGED         ║
║                       ║
╚═══════════════════════╝

If you want to get changes from REMOTE

:diffg RE  

If you want to get changes from BASE

:diffg BA  

If you want to get changes from LOCAL

:diffg LO 

Once the MErged windows looks like what you want
Step 5. Save, Exit, Commit and Clean up

:wqa

save and exit from vi

git commit -m "message"

git clean

Remove extra files (e.g. *.orig) created by diff tool.

• https://gist.github.com/developius/c81f021eb5c5916013dc
• https://www.shellhacks.com/git-config-username-password-store-credentials/
• https://fling.seas.upenn.edu/~giesen/dynamic/wordpress/equivalent-commands-for-git-svn-and-cvs/
• https://stackoverflow.com/questions/161813/how-to-resolve-merge-conflicts-in-git-repository