Add a CODEOWNERS file for GitHub.

Author: jatkinson1000

.github/CODEOWNERS

@@ -0,0 +1,15 @@
+# Each line is a file pattern followed by one or more owners.
+
+# These owners will be the default owners for everything in
+# the repo. Unless a later match takes precedence,
+# will be requested for review when someone opens a pull request.
+*      @jatkinson1000 @jwallwork23
+
+# Order is important; the last matching pattern takes the most
+# precedence. When someone opens a pull request that only
+# modifies specified file types, only that owner will be
+# requested for a review, not the global owner(s).
+
+# You can also use email addresses if you prefer. They'll be
+# used to look up users just like we do for commit author
+# emails.