Shell script to reload contacts

The script checks if the `foia` repository is up to date. If not, it pulls down the latest and runs the loading script.
`git fetch` makes sure the remote updates are present in the repository, but does not merge them into the branch.

The `git log` command shows whether or not there's a difference between the remote branch and the local and spits out the differing changesets one line at a time. If there are no changes, it prints nothing.

Wrapping its results in backticks says "replace everything in backticks with their result". The `if` acts like a Python if, checking for the existence of *anything* in the result. So, if there's a missing update, the `log` command has content, so the `then` is reached. If there's no missing update, `log` has no content, `then` is never reached.