Card: added index for owner
ask page: formatting the cards
configured mailer_sender
new, edit card: 1. similiar styling as on ask-page; 2. removed view tests
Card: added failing spec: front side max 240 chars
Card: implemented: front side max 240 chars
Card: added green test: front side must not be nil
Card: added validation for back side: between 1 and 40 characters
CardsController-spec: create valid card
moved alert, message and sign-out-link to the right
show card: removed link 'Back' to the list of cards
made more convenient to create several cards after each other: 1. after create autofocused button to create the next card; 2. card-form: autofocus front-side
menu: do not show ask random page as link, if we are on the root page