customer model

db/migrate/20191025031631_create_customers.rb

@@ -0,0 +1,11 @@
+class CreateCustomers < ActiveRecord::Migration[5.2]
+  def change
+    create_table :discourse_patrons_customers do |t|
+      t.string :customer_id, null: false
+      t.references :user, foreign_key: true
+      t.timestamps
+    end
+
+    add_index :discourse_patrons_customers, :customer_id, unique: true
+  end
+end