Gemfile in angelo-0.3.1 vs Gemfile in angelo-0.3.2

@@ -3,11 +3,11 @@
 gem 'reel', '~>0.5'
 gem 'tilt', '~>2.0'
 gem 'mime-types', '~>2.4'
 gem 'websocket-driver', '~>0.3'
 
-platform :ruby_20, :ruby_21 do
-  gem 'mustermann', '~>0.3'
+platform :ruby_21 do
+  gem 'mustermann', '~>0.4'
 end
 
 group :development do
   gem 'pry', '~>0.10'
   gem 'pry-nav', '~>0.2'