added colorpicker js library
added js colorpicker to be included in application.js
fixed json not returning after save on slide
added colorpicker to show when editigin slide.
migrate background color field in slides
added some styling to edit slide page
updated schema
Merge branch 'master' of https://github.com/eigilsagafos/light-it-up into change_background_color
Merge pull request #51 from eigilsagafos/change_background_color

Change background color