set up ios

This PR is to *only* set up the ios platform in the client app, so that I can start working. @phoenix16t i saw that you did this too in a pending pull request. 

However, I didn't want to pull yours in since it was bundled with a [database schema change](https://github.com/Reckless-Saturn/restaurant-app/pull/7), which @armandopmj should look over

Can someone pull this in? 
(cc: @lmle)