Added link to Portal-SDK docs

Issue-ID: PORTAL-499

Change-Id: Iad19ecca6f7bb28b6ccef34047adf69f582fb49d
Signed-off-by: Welch, Lorraine (lb2391) <lb2391@att.com>
diff --git a/docs/guides/onap-user/platformadmin.rst b/docs/guides/onap-user/platformadmin.rst
index c0db9d6..8c1107b 100644
--- a/docs/guides/onap-user/platformadmin.rst
+++ b/docs/guides/onap-user/platformadmin.rst
@@ -16,7 +16,9 @@
 technologies, and built-in capabilities such as services, APIs,
 and UI controls. Existing applications can migrate to the Portal
 with the provided APIs and libraries.
-See :ref:`Portal SDK <portal-sdk>`
+See Portal SDK_.
+
+.. _SDK: https://docs.onap.org/en/latest/submodules/portal.git/docs/tutorials/portal-sdk/index.html
 
 Access the ONAP Portal
 ----------------------