Add Alex Good to credits (Whoop!)

docs/topics/credits.md

@@ -178,6 +178,7 @@ The following people have helped make REST framework great.
 * Alexander Lukanin - [alexanderlukanin13]
 * Yamila Moreno - [yamila-moreno]
 * Rob Hudson - [robhudson]
+* Alex Good - [alexjg]
 
 Many thanks to everyone who's contributed to the project.
 
@@ -392,3 +393,4 @@ You can also contact [@_tomchristie][twitter] directly on twitter.
 [alexanderlukanin13]: https://github.com/alexanderlukanin13
 [yamila-moreno]: https://github.com/yamila-moreno
 [robhudson]: https://github.com/robhudson
+[alexjg]: https://github.com/alexjg