Add db:migrate task to CI

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

.gitlab-ci.yml

@@ -115,6 +115,11 @@ bundler:audit:
   script:
     - "bundle exec bundle-audit check --update --ignore OSVDB-115941"
+db-migrate-reset:
+  stage: test
+  script:
+    - RAILS_ENV=test bundle exec rake db:migrate:reset
+
 # Ruby 2.2 jobs
 spec:feature:ruby22: