Auto-promote DanbooruBot to Mod. Auto-create DanbooruBot if it doesn't exist.

config/initializers/system_user.rb

@@ -0,0 +1,10 @@
+require "securerandom"
+
+system = User.find_or_create_by!(name: Danbooru.config.system_user) do |user|
+  user.password = SecureRandom.base64(32)
+end
+
+unless system.is_moderator?
+  system.level = User::Levels::MODERATOR
+  system.save
+end