Create admin user on app start, not in data migration

config/application.rb

@@ -21,5 +21,16 @@ module VanDam
 
     # Don't generate system test files.
     config.generators.system_tests = nil
+
+    config.after_initialize do
+      # Create default admin user if there aren't any users yet
+      if ActiveRecord::Base.connection.table_exists?("users") && User.count == 0
+        User.create(
+          username: "admin",
+          email: "nobody@example.com",
+          admin: true
+        )
+      end
+    end
   end
 end

db/data/20220614214418_create_default_admin_user.rb

@@ -1,15 +0,0 @@
-# frozen_string_literal: true
-
-class CreateDefaultAdminUser < ActiveRecord::Migration[7.0]
-  def up
-    User.create(
-      username: "admin",
-      email: "nobody@example.com",
-      admin: true
-    )
-  end
-
-  def down
-    User.find_by(username: "admin").destroy
-  end
-end