Finish initial implementation of sync and set.
Fix bugs and added testing.
Update README to reflect new additional features.
Set updates the counter associated with the metic if deisred by user.
Add testing for set_metric_by_day's update_counter.
Fixed stylistic changes.
Merge branch 'feature/add_set_and_sync'
Update README.
Change comment and date default.
Merge branch 'feature/add_set_and_sync'
Merge pull request #2 from educreations/master

Added Setting and Syncing of Metric Trackers