Correct spelling mistake

Author: guyroyse

README.md

@@ -28,7 +28,7 @@ It can be found under the `rmutil` folder, and compiles into a static library yo
 
 A minimal module implementing a few commands and demonstarting both the Redis Module API, and use of rmutils.
 
-You can treat it as a template for your module, and extned its code and makefile.
+You can treat it as a template for your module, and extend its code and makefile.
 
 **It includes 3 commands:**