contributing.rst: add Gerrit link

Change-Id: Ia8cbfe802ec681d5ded12b25014b265faed62d6d
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>
diff --git a/docs/contributing.rst b/docs/contributing.rst
index a7ac852..ebbd483 100644
--- a/docs/contributing.rst
+++ b/docs/contributing.rst
@@ -8,8 +8,11 @@
 ############
 
 For familiarity and uniformity with the AOSP development process, Gerrit-based
-review and merge process is followed for dev-boards that have their source
-code hosted here.
+review and merge process is followed for dev-boards that have their source code
+hosted here.
+
+To submit contributions, please use
+`devboardsforandroid Gerrit server <https://gerrit.devboardsforandroid.linaro.org/>`_.
 
 For communities around existing devices that already have a process for their
 contributions, reviewing and merging, we can continue to follow the same.