Make forbidden screen names configurable

app/validators/screen_name_validator.rb

@@ -1,10 +1,7 @@
 # frozen_string_literal: true
 
 class ScreenNameValidator < ActiveModel::EachValidator
-  FORBIDDEN_SCREEN_NAMES = %w[justask_admin retrospring_admin admin justask retrospring about public
-                              notifications inbox sign_in sign_up sidekiq moderation moderator mod administrator
-                              siteadmin site_admin help retro_spring retroospring retrosprlng niisding nllsding
-                              pixeidesu plxeldesu plxeidesu terms privacy linkfilter feedback].freeze
+  FORBIDDEN_SCREEN_NAMES = APP_CONFIG["forbidden_screen_names"].freeze
   FORBIDDEN_SCREEN_NAME_REGEXPS = [/wreciap\z/i].freeze
 
   def validate_each(record, attribute, value)

config/justask.yml.example

@@ -9,6 +9,23 @@ email_from: "noreply@justask.rrerr.net"
 # Name of the "Anonymous" user. (e.g. "Anonymous Coward", "Arno Nym", "Mr. X", ...)
 anonymous_name: "Anonymous"
 
+forbidden_screen_names:
+  - justask_admin
+  - retrospring_admin
+  - admin
+  - justask
+  - retrospring
+  - moderation
+  - moderator
+  - mod
+  - administrator
+  - siteadmin
+  - site_admin
+  - help
+  - retro_spring
+  - retroospring
+  - retrosprlng
+
 # Text shown on the about page (Markdown can be used here)
 about: |
   # About