diff --git a/Gemfile b/Gemfile
index 0bfa003..493ade2 100644
--- a/Gemfile
+++ b/Gemfile
@@ -1,5 +1,6 @@
 source 'https://rubygems.org'
 
+# The gemspec line tells bundler that it can find a .gemspec file alongside the Gemfile.
 gemspec
 gem 'mime-types'
 gem 'wunderbar'