Add Iterator pattern to behavioral patterns list

Author: AdelDaniel

README.md

@@ -95,6 +95,8 @@ Some patterns can be rendered unnecessary in languages that have built-in suppor
 - <strong><a href="behavioral_design_patterns/command/" target="_blank">Command</a></strong>
 - <strong><a href="behavioral_design_patterns/strategy/" target="_blank">Strategy</a></strong>
 - <strong><a href="behavioral_design_patterns/state/" target="_blank">State</a></strong>
+- <strong><a href="behavioral_design_patterns/iterator/" target="_blank">Iterator</a></strong>
+
 ---
 
 ## **Other Patterns Not Exist In GOF**