chore: Add contact note model (#2462)

app/models/note.rb

@@ -0,0 +1,34 @@
+# == Schema Information
+#
+# Table name: notes
+#
+#  id         :bigint           not null, primary key
+#  content    :text             not null
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#  account_id :bigint           not null
+#  contact_id :bigint           not null
+#  user_id    :bigint
+#
+# Indexes
+#
+#  index_notes_on_account_id  (account_id)
+#  index_notes_on_contact_id  (contact_id)
+#  index_notes_on_user_id     (user_id)
+#
+# Foreign Keys
+#
+#  fk_rails_...  (account_id => accounts.id)
+#  fk_rails_...  (contact_id => contacts.id)
+#  fk_rails_...  (user_id => users.id)
+#
+class Note < ApplicationRecord
+  validates :content, presence: true
+  validates :account_id, presence: true
+  validates :contact_id, presence: true
+  validates :user_id, presence: true
+
+  belongs_to :account
+  belongs_to :contact
+  belongs_to :user
+end