Migrate from ledermann/rails-settings to rails-settings-cached which allows global settings

with YAML-defined defaults. Add admin page for editing global settings. Add "site_description"
setting that would show as a paragraph on the frontpage

app/models/setting.rb

@@ -0,0 +1,31 @@
+# frozen_string_literal: true
+
+class Setting < RailsSettings::Base
+  source Rails.root.join('config/settings.yml')
+  namespace Rails.env
+
+  def to_param
+    var
+  end
+
+  class << self
+    def all_as_records
+      vars    = thing_scoped
+      records = vars.map { |r| [r.var, r] }.to_h
+
+      default_settings.each do |key, default_value|
+        next if records.key?(key) || default_value.is_a?(Hash)
+        records[key] = Setting.new(var: key, value: default_value)
+      end
+
+      records
+    end
+
+    private
+
+    def default_settings
+      return {} unless RailsSettings::Default.enabled?
+      RailsSettings::Default.instance
+    end
+  end
+end

app/models/user.rb

@@ -1,6 +1,8 @@
 # frozen_string_literal: true
 
 class User < ApplicationRecord
+  include RailsSettings::Extend
+
   devise :database_authenticatable, :registerable, :recoverable, :rememberable, :trackable, :validatable, :confirmable
 
   belongs_to :account, inverse_of: :user
@@ -14,11 +16,6 @@ class User < ApplicationRecord
   scope :recent,   -> { order('id desc') }
   scope :admins,   -> { where(admin: true) }
 
-  has_settings do |s|
-    s.key :notification_emails, defaults: { follow: false, reblog: false, favourite: false, mention: false, follow_request: true }
-    s.key :interactions, defaults: { must_be_follower: false, must_be_following: false }
-  end
-
   def send_devise_notification(notification, *args)
     devise_mailer.send(notification, self, *args).deliver_later
   end