diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index adbc4e7..7cc9902 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -1,7 +1,7 @@
 image: "ruby:2.1"
 
 before_script:
-  - apt-get update; apt-get install -y check libev-dev net-tools
+  - apt-get update; apt-get install -y check libev-dev net-tools asciidoc
 
 unit_test:
   script: