Initial commit

db/migrate/20180215131129_make_serial_number_unique.rb

@@ -0,0 +1,9 @@
+# encoding: UTF-8
+# frozen_string_literal: true
+
+class MakeSerialNumberUnique < ActiveRecord::Migration[4.2]
+  def change
+    remove_index :members, :sn if index_exists?(:members, :sn)
+    add_index :members, :sn, unique: true
+  end
+end