Ending 'master'

See merge request !102

Require Schleuder version 4.0

See merge request !100

Rename key.oneline to key.summary where important.

See merge request !99

CI: build container image

See merge request !97

Add missing keywords for keywords_admin_* to list config page

See merge request !98

Internally I left it at "oneline" because I'm lazy.

This doesn't yet include tagging the images according the Schleuder API
version they require, but should serve as a base, to begin with.

Base the image on immerda's centos:8

See merge request !94

After precompiling we don't need them anymore.

The image doesn't contain the gems from the 'development' env anyway, so
you already can't use it unchanged to run the app in development mode.
And whenever someone repeats `bundle install` in the container, those
sass-gems will be re-installed, too.

* Avoid assuming that the homedir of user 'user' is in `/home`.
* Rather delete directory contents, not directories.

Require Schleuder v3.6

See merge request !96

Ruby 3.0

See merge request schleuder/schleuder-web!93

Show new list-options of schleuder 3.6.0 on list config page.

See merge request schleuder/schleuder-web!91

# Conflicts:
#   .gitlab-ci.yml

Run CI with ruby v2.7

See merge request schleuder/schleuder-web!92

Update rails to 6.1.2.1

See merge request schleuder/schleuder-web!95

Fixes CVEs (which our app by default isn't affected, but other
configurations might be):
<https://weblog.rubyonrails.org/2021/2/10/Rails-5-2-4-5-6-0-3-5-and-6-1-2-1-have-been-released/>

Required for ruby 3.0 (and rails 6.1)

Update rails to version 6.1

See merge request schleuder/schleuder-web!90

A container image

See merge request schleuder/schleuder-web!85

Catch and report more problems while checking schleuder-api-daemon.

See merge request schleuder/schleuder-web!86

Allow to disallow deletion of keys by subscribers

See merge request schleuder/schleuder-web!89