Gemfile in angelo-0.3.3 vs Gemfile in angelo-0.4.0

@@ -2,15 +2,12 @@
 
 gem 'reel', '~>0.5'
 gem 'tilt', '~>2.0'
 gem 'mime-types', '~>2.4'
 gem 'websocket-driver', '~>0.3'
+gem 'mustermann', '~>0.4'
 
-platform :ruby_21, :ruby_22 do
-  gem 'mustermann', '~>0.4'
-end
-
 group :development do
   gem 'pry', '~>0.10'
   gem 'pry-nav', '~>0.2'
 end
 
@@ -21,6 +18,10 @@
 end
 
 group :test do
   gem 'httpclient', '~>2.5'
   gem 'minitest', '~>5.4'
+
+  platform :mri do
+    gem 'simplecov', '~>0.9.1'
+  end
 end