diff --git a/Gemfile b/Gemfile
index 481a4c6e..c804a77a 100644
--- a/Gemfile
+++ b/Gemfile
@@ -2,3 +2,4 @@ source 'https://rubygems.org'
 gemspec :name => "github-linguist"
 gemspec :name => "github-linguist-grammars"
 gem 'test-unit', require: false if RUBY_VERSION >= '2.2'
+gem 'byebug'
diff --git a/vendor/cache/byebug-3.5.1.gem b/vendor/cache/byebug-3.5.1.gem
new file mode 100644
index 00000000..4a2f7840
Binary files /dev/null and b/vendor/cache/byebug-3.5.1.gem differ
diff --git a/vendor/cache/columnize-0.8.9.gem b/vendor/cache/columnize-0.8.9.gem
new file mode 100644
index 00000000..bc23af26
Binary files /dev/null and b/vendor/cache/columnize-0.8.9.gem differ
diff --git a/vendor/cache/debugger-linecache-1.2.0.gem b/vendor/cache/debugger-linecache-1.2.0.gem
new file mode 100644
index 00000000..723619d3
Binary files /dev/null and b/vendor/cache/debugger-linecache-1.2.0.gem differ