diff --git a/Gemfile.lock b/Gemfile.lock
index 62bc053..581e7c4 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -1,7 +1,7 @@
 PATH
   remote: .
   specs:
-    auction_fun_core (0.4.1)
+    auction_fun_core (0.5.0)
 
 GEM
   remote: https://rubygems.org/
diff --git a/README.md b/README.md
index 220216a..23e599e 100644
--- a/README.md
+++ b/README.md
@@ -132,6 +132,10 @@ This project uses `yadr` as a documentation tool. To generate documentation and
 
 Documentation will be available at `http://localhost:8808`
 
+## External resources
+
+- [Email templates](https://codedmails.com/)
+
 ## License
 
 The gem is available as open source under the terms of the [MIT License](https://opensource.org/licenses/MIT).