Add Question Mark Operator as a ruby til.

README.md

@@ -101,6 +101,7 @@ smart people at [Hashrocket](http://hashrocket.com/).
 - [Override The Initial Sequence Value](ruby/override-the-initial-sequence-value.md)
 - [Parallel Bundle Install](ruby/parallel-bundle-install.md)
 - [Percent Notation](ruby/percent-notation.md)
+- [Question Mark Operator](ruby/question-mark-operator.md)
 - [Squeeze Out The Extra Space](ruby/squeeze-out-the-extra-space.md)
 - [Summing Collections](ruby/summing-collections.md)
 

ruby/question-mark-operator.md

@@ -0,0 +1,22 @@
+# Question Mark Operator
+
+Ruby has a question mark (`?`) operator that works like so
+
+```ruby
+> ?a
+=> "a"
+> ?\s
+=> " "
+> ??
+=> "?"
+> ?a + ?b + ?c
+=> "abc"
+```
+
+It essentially creates single character strings. At least in Ruby 1.9+ it
+does. In versions of Ruby before 1.9, the `?` operator could be used to get
+the ascii character code of the operand character.
+
+h/t Josh Davey
+
+[source](http://stackoverflow.com/questions/16641205/what-does-the-question-mark-operator-do)