diff --git a/Gemfile b/Gemfile
index 30a9f1d..4b782df 100644
--- a/Gemfile
+++ b/Gemfile
@@ -14,3 +14,4 @@ gem "cssminify2"
 gem "json-minify"
 gem "webrick"
 gem "rouge"
+gem "kramdown-math-katex"