Keep your file up to date by pulling in changes from collaborators.
If you're working on something with someone you need to stay up to date with the latest state. So you'll want to pull in any changes that may have been made.
See if Reporobot has made any changes to your 'add-' branch by pulling in from the remote named 'origin' on GitHub:
$ git pull <REMOTENAME> <BRANCHNAME>
If nothing's changed, it will tell you 'Already up-to-date'. If there are changes, it will merge those changes into your local version.
Did Reporobot make changes? Git tells you where changes were made. You can open that file and see Reporobot's updates. Surprise, Reporobot is an artist!
$ git status
$ git pull <REMOTENAME> <REMOTEBRANCH>
$ git fetch --dry-run