Add a /sync/last_modified endpoint that returns an object whose keys are model names and whose values are objects whose keys are model IDs and whose values are datetime_modified ISO 8601 strings.
Add make rule test-sqlite-part for running a particular test in a SQLite testing environment.
Rationale
Resolves https://github.com/dativebase/dativetop/issues/21
Changes
/sync/last_modifiedendpoint that returns an object whose keys are model names and whose values are objects whose keys are model IDs and whose values aredatetime_modifiedISO 8601 strings.test-sqlite-partfor running a particular test in a SQLite testing environment.