Exclude files like Gemfile(.lock), LICENSE from being pushed to _site

_config.yml

@@ -61,6 +61,13 @@ include: ['.htaccess']
 # The language setting is used in /includes/header.html for html-settings
 language: "en"
 
+# Exclude these files from your production _site
+exclude:
+    - Gemfile
+    - Gemfile.lock
+    - LICENSE
+    - README.md
+
 
 #
 #       ____       ____            ____ 

_data/navigation.yml

@@ -1,5 +1,5 @@
 - title: Start
-  url: "/index.html"
+  url: "/"
   side: left
 
 - title: Getting Started