diff --git a/_config.yml b/_config.yml
index 5dc208b..6bc003a 100644
--- a/_config.yml
+++ b/_config.yml
@@ -1,6 +1,9 @@
 #------------------------------------------------------------
 # Values for this lesson.
 #------------------------------------------------------------
+exclude:
+  - vendor
+  - Gemfile.lock
 
 # Which carpentry is this ("swc", "dc", "lc", or "cp")?
 # swc: Software Carpentry