More verbose sign in error message

config/locales/en.yml

@@ -2,4 +2,10 @@
 # See https://github.com/svenfuchs/rails-i18n/tree/master/rails%2Flocale for starting points.
 
 en:
-  hello: "Hello world"
+  spree:
+
+  devise:
+    failure:
+      invalid: | 
+        Invalid email or password. 
+        Were you a guest last time?  Perhaps you need to create an account or reset your password.