diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 85d9c17..f46c980 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -10,6 +10,7 @@ stages:
 
 before_script:
   - set -euxo pipefail
+  - gem install bundler -v "~>1.0"
   - bundle install --path vendor
 
 site:
@@ -18,4 +19,4 @@ site:
     paths:
       - _site/*
   script:
-    - bundle exec jekyll build --config _config.yml
\ No newline at end of file
+    - bundle exec jekyll build --config _config.yml