Non-authenticated user cannot ask questions
Refactor sign_in_spec and ask_question_spec - move sign in code to feature_helper
Add Sign out behavior
Fix bug: possible to open edit page for question with answers. QuestionController GET #edit redirects to #show with corresponding error message
Add feature spec that user cannot open edit page for question with answers
Add sign up behavior
Refactor feature/sign_in_spec
Refactor feature/ask_question_spec
User cannot edit or delete another user's question