Add references between projects and todos

db/migrate/20251027123148_add_project_id_to_todos.rb

@@ -0,0 +1,5 @@
+class AddProjectIdToTodos < ActiveRecord::Migration[8.1]
+  def change
+    add_reference :todos, :project, null: false, foreign_key: true
+  end
+end

db/schema.rb

@@ -10,7 +10,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema[8.1].define(version: 2025_10_27_122702) do
+ActiveRecord::Schema[8.1].define(version: 2025_10_27_123148) do
   create_table "projects", force: :cascade do |t|
     t.boolean "active", default: true, null: false
     t.datetime "created_at", null: false
@@ -24,6 +24,10 @@ ActiveRecord::Schema[8.1].define(version: 2025_10_27_122702) do
     t.text "description"
     t.string "name"
     t.integer "priority", default: 1, null: false
+    t.integer "project_id", null: false
     t.datetime "updated_at", null: false
+    t.index ["project_id"], name: "index_todos_on_project_id"
   end
+
+  add_foreign_key "todos", "projects"
 end