* add AlertSchedule model and relationships
change table structure to match the expected layout
* Update maint schedule map ui
* better index name
* Laravel queries
fix some issues with the ui: restricting start incorrectly and loading empty days error
* handle date limiting properly
* Another attempt add schedule constraints
* use Auth
* Update WorldMap widget to use check isUnderMaintenance
* Rename 275.sql to 276.sql
* Rename 276.sql to 277.sql
