refactor avatar validations
gem carrierwave
generate carrierwave uploader: icon, add icon field to Avatar and AP
mount IconUploader to Avatar and AP, fix prev changed validations
avatars controller created
rm public/index.html
fix typo
set ruby version in gemfile
avatars_controller tests
skip uniqueness tests for now
gem slim-rails
avatars/index.html.slim, convert application.html.erb to slim, viewport
avatars/show.html.slim
gem simple_form