From 4c6825ae9b4e40ac686e8b48c6e9cb0fb67b15ed Mon Sep 17 00:00:00 2001
From: Nai-Yuan Chen <MitsunChieh@users.noreply.github.com>
Date: Tue, 29 Nov 2016 14:39:54 +0800
Subject: [PATCH] README.md, add using example for ruby on rails

---
 README.md | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/README.md b/README.md
index f6f5500..0b43d5c 100644
--- a/README.md
+++ b/README.md
@@ -32,6 +32,23 @@ function is_temp_mail($mail) {
     return in_array(explode('@', $mail)[1], $mail_domains_ko);
 }
 ```
+Ruby on Rails
+
+In resource model, usually it is `user.rb`
+```Ruby
+before_validation :reject_email_blacklist
+
+def reject_email_blacklist
+  blacklist = File.read('config/disposable_email_blacklist.conf').split("\n")
+
+  if blacklist.include?(email.split('@')[1])
+    errors[:email] << 'invalid email'
+    return false
+  else
+    return true
+  end
+end
+```
 
 Contributing
 ============