init
DI setup
Configure tests
Provide a 'Firebase' service and inject it into both fns
Generate sourcemaps and coverage
Use decorator instead of runtime patching
Test structure
Failing test for generating a Firebase reference
Use MockFirebase
Test that path is called with the model
Firebase should be a regular dep
Use the default mockfirebase base
Use chai-sinon for easy sinon access
Support listening on particular model properties with #subscribe