Gemfile in x25519-1.0.6 vs Gemfile in x25519-1.0.7

@@ -3,9 +3,10 @@
 source "https://rubygems.org"
 
 gemspec
 
 group :development, :test do
+  gem "coveralls", require: false
   gem "rake", require: false
   gem "rake-compiler", "~> 1.0", require: false
   gem "rspec", "~> 3.7", require: false
   gem "rubocop", "0.52.1", require: false
 end