Build Jekyll in deploy jobs

.gitlab-ci.yml

 image: jekyll/builder
 
 stages:
-  - build
   - deploy
 
 variables:
@@ -13,29 +12,31 @@ before_script:
   - apk add lftp
   - ./scripts/ci_fix_baseurl.sh
 
-build-jekyll:
-  stage: build
-  cache:
-    key: gems
-    paths:
-    - "/usr/local/bundle/cache"
-  script:
-  - bundle install
-  - jekyll build -d public
-
 deploy-prod:
   stage: deploy
   script:
+  - bundle install
+  - jekyll build -d public
   - ./scripts/ci_deploy_site.sh public
+  cache:
+    key: gems
+    paths:
+    - "/usr/local/bundle/cache"
   only:
   - master
 
 pages:
   stage: deploy
   script:
-    - echo "Nothing to do."
+  - bundle install
+  - jekyll build -d public
+  - echo "Nothing to do."
   artifacts:
     paths:
     - public
+  cache:
+    key: gems
+    paths:
+    - "/usr/local/bundle/cache"
   only:
   - develop