Add rails-settings-cached, use for initial feature flags

db/migrate/20230217084310_create_settings.rb

@@ -0,0 +1,15 @@
+class CreateSettings < ActiveRecord::Migration[7.0]
+  def self.up
+    create_table :settings do |t|
+      t.string  :var,        null: false
+      t.text    :value,      null: true
+      t.timestamps
+    end
+
+    add_index :settings, %i(var), unique: true
+  end
+
+  def self.down
+    drop_table :settings
+  end
+end