Fixes install --github so it append README.md

- Before it replaced the README.md file with new content, now its
append content in a more proper manner. If no README.md exists its
still created.
- .localeapp was sometimes injected without space on the previous
.gitignore key, now it ensure newline.
Merge pull request #152 from futhr/feature/append-readme

Fixes install --github so it append README.md