GitLab

Refactors assemble script, and other changes

See merge request !2

Next commit contains the rest of the changes.

This reverts commit c4acd3d0.

This reverts commit fde89930.

Fix exit code of test/run.

Bundler fixes

See merge request !1

Added nodejs and npm dependencies and pinned Rails to 5.2 and 6.0

Use rails-test-app images

Run as app-user.

Moves test task to script.

Updates Dockerfile to be consistent with debian-buster base image.
Removes build.sh and test.sh (use `make' and `make test').