When repository contains a Slack type hook,
it changes original payload content.

This patch fixes it by using a local object to store
newly created Slack payload instead of assigning
back to the same variable.

- Update locales

- update required version of git-module for #2373

- User profile un/follow
- List user's followers/following

- #2153 remove require for gravatar

We can look at the PushCommits object to see how many commits were
included in a commit, and add some template logic to only show the
comparison link when there are at least 2 commits in a push. We also
correct the link to display the number of commits.