switch install state to db

app/models/setup_state.rb

@@ -0,0 +1,16 @@
+class SetupState < ApplicationRecord
+  def self.installed?
+    first&.installed? || false
+  end
+
+  def self.mark_installed!
+    record = first_or_initialize
+    record.installed = true
+    record.installed_at ||= Time.current
+    record.save!
+  end
+
+  def self.reset!
+    delete_all
+  end
+end