refactor feedback.rb to have validation and association to sender and recipient
refactor feedback.rb to have validation and association to sender and recipient

tgoldenberg/Speak-It,nyc-dragonflies-2015/Speak-It,tgoldenberg/Speak-It,tgoldenberg/Speak-It,nyc-dragonflies-2015/Speak-It,nyc-dragonflies-2015/Speak-It