move puma to dev

Gemfile

@@ -8,8 +8,6 @@ gem 'rails', '~> 5.2.0'
 
 # Use sqlite3 as the database for Active Record
 gem 'sqlite3', '~> 1.3', '< 1.4'
-# Use Puma as the app server
-gem 'puma'
 
 # Use SCSS for stylesheets
 gem 'sass-rails',
@@ -40,6 +38,7 @@ gem 'unidecoder'
 gem 'jquery-rails'
 
 group :development do
+  gem 'puma'
   # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
   gem 'web-console', '>= 3.3.0'
   gem 'listen', '>= 3.0.5', '< 3.2'