add player rating to the db

main-server/db/migrate/20261005000000_add_rating_to_users.rb

@@ -0,0 +1,7 @@
+class AddRatingToUsers < ActiveRecord::Migration[8.1]
+  def change
+    # Neutral initial rating. The value lives in the DB; in the future it
+    # will be recalculated based on player performance.
+    add_column :users, :rating, :integer, null: false, default: 100
+  end
+end