temporary fixing 500 on lessons with no teacher
Merge branch 'hotfix/teachers_in_shedule_check'

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

* hotfix/teachers_in_shedule_check:
  temporary fixing 500 on lessons with no teacher
  fix main_text_align in welcome_index
  fix photo_slider
  replace text
  add mini_magick gem
  edit db/schema.rb
  add cktext_area to news
  add label about fotos
  change size in photosliders
  fix teachers index
  fix fotorama slider
Merge branch 'release/hotfix_on_schedule'

* release/hotfix_on_schedule: