added attributes to job offers show and edit #5,#6
added datepicker, #5
added query turbo link, #5
save start and end date, #5
fixed error with empty value, #5
renamed end_time to end_date, description datatype to text, start_date & end_date type to date #5, #6
added attribute labels to show, added delete button, style show view, #5
adapt create/update style to view style, #6
initial work in students profile
Merge remote-tracking branch 'origin/crud-job-offers' into develop-js-student-profile

Conflicts:
	Gemfile
	Gemfile.lock
	db/schema.rb
fixed some merge bullshit
some rails magic
changed layout of overview list
job title links to detail page
list shows jobs sorted by created_at
#4
adjusted Test to match layout changes
changed schema
Merge branch 'develop-ja' of https://github.com/tkowark/hpi-hiwi-portal into develop-ja
 added plpgsql extension to schema.rb
nur das Dokument geöffnet. Keine Codeänderung
check presence of attributes in job_offers, #6
check if start date is before end date in job offers #6