diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 62e06683124f82790c87d83b861b42cf07018ac4..7d19f55aca38a7e0a483976c82c343256cd80dd4 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -339,3 +339,16 @@ pages:
       - public
   only:
     - master
+
+# Insurance in case a gem needed by one of our releases gets yanked from
+# rubygems.org in the future.
+cache gems:
+  only:
+    - tags
+  variables:
+    SETUP_DB: "false"
+  script:
+    - bundle package --all --all-platforms
+  artifacts:
+    paths:
+      - vendor/cache