Add new column
Add #monthly? predicate
Add a validation context
Validate numericality of day_of_month
Add #weekly? predicate

#weekly? and #monthly? are mutually exclusive
Do not allow weekly and monthly frequency at the same time
Add form input for day_of_month
Change today scope to check for day_of_month
Verify monthly events are caught, too
Add changes for v1.3.0
Merge branch 'feature/monthly-expectations'