Add links to contributor GitHub profiles

CONTRIBUTORS.md

@@ -2,21 +2,21 @@
 
 This is a list of everyone who has made significant contributions to spaCy, in alphabetical order. Thanks a lot for the great work!
 
-* Adam Bittlingmayer, @bittlingmayer
-* Andreas Grivas, @andreasgrv
-* Chris DuBois, @chrisdubois
-* Christoph Schwienheer, @chssch
-* Henning Peters, @henningpeters
-* Ines Montani, @ines
-* J Nicolas Schrading, @NSchrading
-* Jordan Suchow, @suchow
-* Kendrick Tan, @kendricktan
-* Liling Tan, @alvations
-* Matthew Honnibal, @honnibal
-* Maxim Samsonov, @maxirmx
-* Oleg Zd, @olegzd
-* Sam Bozek, @sambozek
-* Vsevolod Solovyov, @vsolovyov
-* Wah Loon Keng, @kengz
-* Wolfgang Seeker, @wbwseeker
-* Yubing Dong, @tomtung
+* Adam Bittlingmayer, [@bittlingmayer](https://github.com/bittlingmayer)
+* Andreas Grivas, [@andreasgrv](https://github.com/andreasgrv)
+* Chris DuBois, [@chrisdubois](https://github.com/chrisdubois)
+* Christoph Schwienheer, [@chssch](https://github.com/chssch)
+* Henning Peters, [@henningpeters](https://github.com/henningpeters)
+* Ines Montani, [@ines](https://github.com/ines)
+* J Nicolas Schrading, [@NSchrading](https://github.com/NSchrading)
+* Jordan Suchow, [@suchow](https://github.com/suchow)
+* Kendrick Tan, [@kendricktan](https://github.com/kendricktan)
+* Liling Tan, [@alvations](https://github.com/alvations)
+* Matthew Honnibal, [@honnibal](https://github.com/honnibal)
+* Maxim Samsonov, [@maxirmx](https://github.com/maxirmx)
+* Oleg Zd, [@olegzd](https://github.com/olegzd)
+* Sam Bozek, [@sambozek](https://github.com/sambozek)
+* Vsevolod Solovyov, [@vsolovyov](https://github.com/vsolovyov)
+* Wah Loon Keng, [@kengz](https://github.com/kengz)
+* Wolfgang Seeker, [@wbwseeker](https://github.com/wbwseeker)
+* Yubing Dong, [@tomtung](https://github.com/tomtung)