Formalize Mongo Schema

[will2041]

Taking some lessons from Steven Lott's PyData presentation: http://pydata.org/dc2016/schedule/presentation/40/

https://twitter.com/s_lott

https://slott56.github.io/no-sql-doesnt-mean-no-schema/assets/player/KeynoteDHTMLPlayer.html#0

We can formalize the Mongo schemas using JSON and relying on JSON validation to ensure that we never even instantiate an object that doesn't match our defined schema.