first commit

app/models/application_record.rb

@@ -0,0 +1,3 @@
+class ApplicationRecord < ActiveRecord::Base
+  primary_abstract_class
+end

app/models/todo.rb

@@ -0,0 +1,3 @@
+class Todo < ApplicationRecord
+  validates :title, presence: true, length: { maximum: 255 }
+end