Add link to contributor graph under 'Contributors'.

diff --git a/README.md b/README.md
index e2bb3db..ed3e086 100644
--- a/README.md
+++ b/README.md

@@ -48,6 +48,8 @@
 
 Contributors
 --------------
+### [GitHub Contributor Graph](https://github.com/unittest-cpp/unittest-cpp/contributors) ###
+
 ### Current Maintainers: ###
 * Patrick Johnmeyer ([email protected]) @pjohnmeyer
 * Charles Nicholson ([email protected]) @charlesnicholson