init project

spec/mailers/previews/user_mailer_preview.rb

@@ -0,0 +1,6 @@
+# Preview all emails at http://localhost:3000/rails/mailers/user_mailer
+class UserMailerPreview < ActionMailer::Preview
+  def register_email
+    UserMailer.register_email("63595834@qq.com", "123456")
+  end
+end

spec/mailers/user_mailer_spec.rb

@@ -0,0 +1,5 @@
+require "rails_helper"
+
+RSpec.describe UserMailer, type: :mailer do
+  pending "add some examples to (or delete) #{__FILE__}"
+end