Add Who Are My Ancestors as a ruby til.

README.md

@@ -218,6 +218,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Summing Collections](ruby/summing-collections.md)
 - [Uncaught Exceptions In Pry](ruby/uncaught-exceptions-in-pry.md)
 - [`undef_method` And The Inheritance Hierarchy](ruby/undef-method-and-the-inheritance-hierarchy.md)
+- [Who Are My Ancestors?](ruby/who-are-my-ancestors.md)
 - [Zero Padding](ruby/zero-padding.md)
 
 ### tmux

ruby/who-are-my-ancestors.md

@@ -0,0 +1,17 @@
+# Who Are My Ancestors?
+
+Ruby's `Module` class provides the
+[`#ancestors`](http://ruby-doc.org/core-2.1.0/Module.html#method-i-ancestors)
+method. This method allows you to determine the ancestors (parents,
+grandparents, etc.) of a given class.
+
+```ruby
+> 5.class.ancestors
+=> [Fixnum, Integer, Numeric, Comparable, Object, PP::ObjectMixin, Kernel, BasicObject]
+> Array.ancestors
+=> [Array, Enumerable, Object, PP::ObjectMixin, Kernel, BasicObject]
+> Class.ancestors
+=> [Class, Module, Object, PP::ObjectMixin, Kernel, BasicObject]
+> BasicObject.ancestors
+=> [BasicObject]
+```