CONTRIBUTING.md: link to branch next

CONTRIBUTING.md

@@ -2,7 +2,7 @@
 
 Contributions and pull requests are welcome.  Please take note of the following guidelines:
 
-* **Work and push on `next` branch**. `git remote update; git checkout origin/next` before hacking. Exceptions for bugs in `master` branch and simple typo fix.
+* **Work and push on [next](https://github.com/jreybert/vimagit/tree/next) branch**. `git remote update; git checkout origin/next` before hacking. Exceptions for bugs in `master` branch and simple typo fix.
 * Always rebase your work before push: `git pull --rebase origin next`
 * Adhere to the existing style as much as possible; notably, tabulation indents and long-form keywords. Try to add comments for important changes/addings.
 * Make targeted pull request: propose one feature/bugfix, and push only commit(s) related to this feature/bugfix.