diff --git a/.ruby-version b/.ruby-version
new file mode 100644
index 000000000..8e8299dcc
--- /dev/null
+++ b/.ruby-version
@@ -0,0 +1 @@
+2.4.2
diff --git a/docs/_config.yml b/docs/_config.yml
index c3eb8ba92..b995e943a 100644
--- a/docs/_config.yml
+++ b/docs/_config.yml
@@ -10,7 +10,7 @@ safe: false
 lsi: false
 exclude: [README.md]
 
-plugins::
+plugins:
   - jekyll-redirect-from
   - jekyll-seo-tag