Added documentation for validates_inclusion_of

1 files changed, 13 insertions, 0 deletions

diff --git a/railties/doc/guides/source/activerecord_validations_callbacks.txt b/railties/doc/guides/source/activerecord_validations_callbacks.txt
index f61bea9d3d..4b4b9b4b17 100644
--- a/railties/doc/guides/source/activerecord_validations_callbacks.txt
+++ b/railties/doc/guides/source/activerecord_validations_callbacks.txt
@@ -176,6 +176,19 @@ The default error message for +validates_format_of+ is "_is invalid_".
 
 === The +validates_inclusion_of+ helper
 
+This helper validates that the attributes' values are included in a given set. In fact, this set can be any enumerable object.
+
+[source, ruby]
+------------------------------------------------------------------
+class Coffee < ActiveRecord::Base
+  validates_inclusion_of :size, :in => %w(small medium large), :message => "%s is not a valid size"
+end
+------------------------------------------------------------------
+
+The +validates_inclusion_of+ helper has an option +:in+ that receives the set of values that will be accepted. The +:in+ option has an alias called +:within+  that you can use for the same purpose, if you'd like to. In the previous example we used the +:message+ option to show how we can personalize it with the current attribute's value, through the +%s+ format mask.
+
+The default error message for +validates_inclusion_of+  is "_is not included in the list_".
+
 === The +validates_length_of+ helper
 
 === The +validates_numericallity_of+ helper