new branch
bla
migrations
answer class added, last solution remembered
tried to fix show-lessons-only-if-previous-chapter-is-finished. still contains an error
answer retrieving fixed, still contains a bug
database table answers fixed, story finished
changeds on the chapter csses
report4 added, screenshot zip added, old screenshots removed
Merge remote-tracking branch 'origin/rememberUsersLessonSolutions'

Conflicts:
	app/controllers/lessons_controller.rb
	app/models/lesson.rb
	db/schema.rb