Added proper CODEOWNERS

Author: john-h-k

CODEOWNERS

@@ -1,11 +1,12 @@
 # Lines starting with '#' are comments.
 # Each line is a file pattern followed by one or more owners.
 
-# These owners will be the default owners for everything in the repo.
-*       @johnkellyoxford
+# Defualt owner
+* @johnkellyoxford
 
-# Order is important. The last matching pattern has the most precedence.
-# So if a pull request only touches javascript files, only these owners
-# will be requested to review.
+# File endings owner
+*.xaml @NightRaven3142
+*.xaml.cs @NightRaven3142 @nathanmc158 @johnkellyoxford
+*.md @NightRaven3142 @nathanmc158 @johnkellyoxford
 
 # You can also use email addresses if you prefer.