Model data needed for vida

[smesdaghi]

At a later point we'll want to support some disconnected opperations. Additionally, we likely need to keep track of the changes made to the people (and potentially shelters) so that we can generate more meaning full statistics.

[smesdaghi]

In order for the application to easily access the objects we'll have people and shelters as django models as opposed to using geogig. Since people will not have a geometry associated with them, using geogig will be a stretch. We'll use a method similar to postgis's timetravel. We'll keep it simple for the first pass b