You need to fork, then pull from and push to your own repo. That is:
1. Visit
https://github.com/Gnurou/tagainijisho/ (while logged in)
2. Click the 'Fork' button in the upper right to get your own copy of the repo.
3. It should redirect you to your repo at
https://github.com/YOURNAME/tagainijisho
4. Clone your repo with "git clone g...@github.com:YOURNAME/tagainijisho.git"
5. Make your changes.
6. Push your changes.
7. Create a pull request on github (use the "Pull Request" link on the
repo page).
The problem you seem to be having is that in step 4 you pulled from
Alexandre (Gnurou)'s repo, rather than your own.
I hope this helps. I'm no git wizard myself, so any difficulty you
have with these instructions may be my fault. Ask again if you need
more help.
--
Tracy Poff