Rails and PostGIS
Please read these two blog posts by Daniel Azuma for background (they are from 2011 but are still quite relevant):
Then install PostGIS and make sure it works well with Rails by following the Install documentation for active-record-postgis-adapter.
Please submit questions or problems installing PostGIS to the Starmonkeys Google Group.
I will post a google hangout link in the whiteboard at the beginning of class.