Remove rails_admin

This is now broken since more than half a year, so I think we can just
remove it.

Podmins shouldn't use this anyway, because it does bad things, like
replacing NULL with an empty string when editing something. If we really
need an admin interface for something, we should add it to our own admin
panel at /admins/dashboard.

Fixes #7027 and #6413

closes #7440

Changelog.md

 # 0.6.6.0
 
 ## Refactor
+* Remove rails\_admin [#7440](https://github.com/diaspora/diaspora/pull/7440)
 
 ## Bug fixes
 * Make photo upload button hover text translatable [#7429](https://github.com/diaspora/diaspora/pull/7429)

Gemfile

@@ -217,10 +217,6 @@ gem "thor", "0.19.1"
 # gem "therubyracer", :platform => :ruby
 
 group :production do # we don"t install these on travis to speed up test runs
-  # Administration
-
-  gem "rails_admin", "0.8.1"
-
   # Analytics
 
   gem "rack-google-analytics", "1.2.0"

Gemfile.lock

@@ -104,13 +104,6 @@ GEM
     chunky_png (1.3.8)
     cliver (0.3.2)
     coderay (1.1.1)
-    coffee-rails (4.2.1)
-      coffee-script (>= 2.2.0)
-      railties (>= 4.0.0, < 5.2.x)
-    coffee-script (2.4.1)
-      coffee-script-source
-      execjs
-    coffee-script-source (1.12.2)
     compass (1.0.3)
       chunky_png (~> 1.2)
       compass-core (~> 1.0.2)
@@ -236,8 +229,6 @@ GEM
     fog-xml (0.1.2)
       fog-core
       nokogiri (~> 1.5, >= 1.5.11)
-    font-awesome-rails (4.7.0.1)
-      railties (>= 3.2, < 5.1)
     formatador (0.2.5)
     fuubar (2.2.0)
       rspec-core (~> 3.0)
@@ -347,9 +338,6 @@ GEM
     jsonpath (0.5.8)
       multi_json
     jwt (1.5.6)
-    kaminari (0.17.0)
-      actionpack (>= 3.0.0)
-      activesupport (>= 3.0.0)
     kgio (2.11.0)
     leaflet-rails (0.7.7)
     listen (3.1.5)
@@ -390,7 +378,6 @@ GEM
     mysql2 (0.4.5)
     naught (1.1.0)
     nenv (0.3.0)
-    nested_form (0.3.2)
     nio4r (2.0.0)
     nokogiri (1.7.1)
       mini_portile2 (~> 2.1.0)
@@ -492,9 +479,6 @@ GEM
       multi_json (>= 1.3.6)
       rack (>= 1.1)
     rack-piwik (0.3.0)
-    rack-pjax (0.8.0)
-      nokogiri (~> 1.5)
-      rack (~> 1.1)
     rack-protection (1.5.3)
       rack
     rack-rewrite (1.5.1)
@@ -571,20 +555,6 @@ GEM
     rails-timeago (2.16.0)
       actionpack (>= 3.1)
       activesupport (>= 3.1)
-    rails_admin (0.8.1)
-      builder (~> 3.1)
-      coffee-rails (~> 4.0)
-      font-awesome-rails (>= 3.0, < 5)
-      haml (~> 4.0)
-      jquery-rails (>= 3.0, < 5)
-      jquery-ui-rails (~> 5.0)
-      kaminari (~> 0.14)
-      nested_form (~> 0.3)
-      rack-pjax (~> 0.7)
-      rails (~> 4.0)
-      remotipart (~> 1.0)
-      safe_yaml (~> 1.0)
-      sass-rails (>= 4.0, < 6)
     railties (4.2.8)
       actionpack (= 4.2.8)
       activesupport (= 4.2.8)
@@ -600,7 +570,6 @@ GEM
     redis (3.3.3)
     redis-namespace (1.5.3)
       redis (~> 3.0, >= 3.0.4)
-    remotipart (1.3.1)
     request_store (1.3.2)
     responders (2.3.0)
       railties (>= 4.2.0, < 5.1)
@@ -887,7 +856,6 @@ DEPENDENCIES
   rails-assets-perfect-scrollbar (= 0.6.16)!
   rails-i18n (= 4.0.8)
   rails-timeago (= 2.16.0)
-  rails_admin (= 0.8.1)
   rb-fsevent (= 0.9.8)
   rb-inotify (= 0.9.8)
   redcarpet (= 3.4.0)

config/routes.rb

@@ -10,10 +10,6 @@ Diaspora::Application.routes.draw do
 
   resources :report, except: %i(edit new show)
 
-  if Rails.env.production?
-    mount RailsAdmin::Engine => '/admin_panel', :as => 'rails_admin'
-  end
-
   constraints ->(req) { req.env["warden"].authenticate?(scope: :user) &&
                         req.env['warden'].user.admin? } do
     mount Sidekiq::Web => '/sidekiq', :as => 'sidekiq'