diff --git a/CONTRIBUTING.md b/CONTRIBUTING.md
index 8a01ce4..42109d3 100644
--- a/CONTRIBUTING.md
+++ b/CONTRIBUTING.md
@@ -65,8 +65,8 @@ included in the project:
 4. Install the [Jekyll](https://github.com/jekyll/jekyll/) gem and dependencies to preview locally:
 
     ```bash
-    # Install the needed gems
-    gem install jekyll jekyll-sitemap pygments.rb
+    # Install the needed gems through Bundler
+    bundle install
     # Build and open _site/index.html in your browser...
     jekyll build [--watch]
     # ...or run a local server to easily develop:
diff --git a/Gemfile.lock b/Gemfile.lock
index a5e7093..c68e4ec 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -124,6 +124,3 @@ PLATFORMS
 
 DEPENDENCIES
   github-pages
-
-BUNDLED WITH
-   1.10.6