diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index 3740cf4..2fc6f64 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,4 +1,8 @@
-image: ruby:2.3
+image: ruby:2.4
+
+variables:
+  JEKYLL_ENV: production
+  LC_ALL: C.UTF-8
 
 pages:
   stage: deploy