Merge branch 'hotfix/teachers_in_shedule_check'

* hotfix/teachers_in_shedule_check:
  temporary fixing 500 on lessons with no teacher
Merge branch 'release/hotfix_on_schedule'

* release/hotfix_on_schedule:
change last hotfix
Merge branch 'hotfix/change_last_hotfix' into develop

* hotfix/change_last_hotfix:
  change last hotfix