chore: Add contact note model (#2462)

db/migrate/20210618073042_create_notes.rb

@@ -0,0 +1,11 @@
+class CreateNotes < ActiveRecord::Migration[6.0]
+  def change
+    create_table :notes do |t|
+      t.text :content, null: false
+      t.references :account, foreign_key: true, null: false
+      t.references :contact, foreign_key: true, null: false
+      t.references :user, foreign_key: true
+      t.timestamps
+    end
+  end
+end