Add job_offers table
Add JobOffer with basic validations
Condense city and country into location
Add JobOffer factory
WIP: add job_offers#index
Reduce let!(:user) definitions
Add User#student? predicate
Define abilities for job offers
Add cancan to resource
Use shared context
Add job_offers#show
Add spring
Add job offer CRUD
Rename JobOffer#public to #rgsoc_only
Provide descriptive headings
Add job offers to main nav
Show hint when list is empty
Merge branch 'feature/add-job-offers'