users can update location on settings page

recruiters can use professional filters

recruiters can filter by law focus

fix bug: prevent appointment slots being `null`

fix bug: add clearing of appointment slots for hosts when switching events

fix bug: allow students and pupils to save their language levels

add ‘Metallindustrie’ as a industry option

add ‘Full-time’ and ‘Part-time’ as position options

slogan of professional is visible in chat header and chat overview

host name is visible in event cards