Add password authentication and pry

We added pry for the purpose of debugging our session bugs.
Merge branch 'release-0' of https://github.com/mathildemouw/DBC_flashcard_project into release-0

Conflicts:
	app/views/index.erb
Merge branch 'release-0' of https://github.com/mathildemouw/DBC_flashcard_project into release-0

Conflicts:
	Gemfile.lock
Merge pull request #20 from mathildemouw/sessions

Sessions