Merge branch 'ci' into 'master'

.gitlab-ci.yml

.idea/encodings.xml

.idea/misc.xml

.idea/modules.xml

.idea/tdt4242-base.iml

.idea/vcs.xml

.idea/workspace.xml

backend/Procfile

backend/secfit/secfit/djangoHeroku.py

backend/secfit/secfit/settings.py

backend/secfit/workouts/admin.py

backend/secfit/workouts/migrations/0004_workoutlike.py

backend/secfit/workouts/models.py

backend/secfit/workouts/urls.py

backend/secfit/workouts/views.py

frontend/Procfile

frontend/www/exercise.html

frontend/www/scripts/exercise.js

frontend/www/scripts/workouts.js

frontend/www/styles/style.css