Make the test output shorter and more readable

[ci skip]

.gitlab-ci.yml

@@ -27,7 +27,7 @@ test:
   stage: test
   before_script: *before_script
   script:
-    - bundle exec rake test
+    - bundle exec rake -s --suppress-backtrace . test
   except:
     - triggers
 
@@ -36,7 +36,7 @@ deploy:
   environment: production
   before_script: *before_script
   script:
-    - bundle exec rake deploy
+    - bundle exec rake -s --suppress-backtrace . deploy
   tags:
     - doc
   only:
@@ -48,7 +48,7 @@ deploy:
 deadlinks:
   stage: deploy
   script:
-    - bundle exec rake testlinks
+    - bundle exec rake -s --suppress-backtrace . testlinks
   allow_failure: true
   except:
     - triggers