Add reminder feature

spec/models/reminder_spec.rb

@@ -0,0 +1,17 @@
+require 'rails_helper'
+
+RSpec.describe Reminder, type: :model do
+  subject { build(:reminder) }
+
+  describe 'validations' do
+    %w[title body date].each do |attribute|
+      describe attribute do
+        it 'must be present' do
+          expect(subject).to be_valid
+          subject[attribute] = nil
+          expect(subject).to_not be_valid
+        end
+      end
+    end
+  end
+end