Table Module: Field 'id' can not be NULL

I've been having problems adding id fields to tables. For example, I can create a new table with two fields: id (of type id) and name (of type string). When I navigate to the Data page and Create a new entry for the table, I receive this error when clicking "Save":

DreamFactory Table Module
Field 'id' can not be NULL.

I originally had this problem when I was setting up a postgres database, but I have the same problem with a fresh install using the default sqlite database (DF v2.1.0 installed from github).