Actually only load rails admin in production mode

This is what I think 28f8db51e7 was supposed to do.

With the initializer in an "unless Rails.env.production?" block
the entire initializer was being ignored in production mode and
loaded in all other environments, but Rails Admin was still
loading regardless of that. 😁

This only loads rails admin in production and excludes it from
all other environments. Also keeps non-admins out of /admin_panel
(without the initializer it was free-for-all) and temp fixes #3210
until a new gem is released.

Gemfile

@@ -25,7 +25,6 @@ gem 'omniauth-tumblr'
 gem 'omniauth-twitter'
 
 gem 'twitter', '2.0.2'
-gem 'rails_admin'
 
 # mail
 
@@ -36,6 +35,7 @@ gem 'newrelic_rpm'
 gem "rpm_contrib", "~> 2.1.7"
 
 group :production do # we don't install these on travis to speed up test runs
+  gem 'rails_admin'
   gem 'rack-ssl', :require => 'rack/ssl'
   gem 'rack-rewrite', '~> 1.2.1', :require => false
   gem 'rack-piwik', :require => 'rack/piwik'

config/initializers/rails_admin.rb

@@ -1,6 +1,6 @@
 # RailsAdmin config file. Generated on March 24, 2012 15:34
 # See github.com/sferik/rails_admin for more informations
-unless Rails.env.production?
+if Rails.env.production?
 RailsAdmin.config do |config|
    config.authorize_with do 
     redirect_to main_app.root_path unless current_user.try(:admin?)

config/routes.rb

@@ -3,7 +3,9 @@
 #   the COPYRIGHT file.
 
 Diaspora::Application.routes.draw do
-  mount RailsAdmin::Engine => '/admin_panel', :as => 'rails_admin'
+  if Rails.env.production?
+    mount RailsAdmin::Engine => '/admin_panel', :as => 'rails_admin'
+  end
 
   get 'oembed' => 'posts#oembed', :as => 'oembed'
   # Posting and Reading