Merge pull request #14 from vtoulemonde/modification

Add gem unicorn in Gemfile. Create file config/unicorn.rb.
Merge pull request #15 from vtoulemonde/favorites

Favorites
Multiple photos upload for visits now working
Icone favorite on the top right of each place
Merge branch 'master' of https://github.com/vtoulemonde/visit_places_app into favorites
Remove unused file addphoto.html.erb