Docs: Add issue tracking guideline

Signed-off-by: Anton Komlev <anton.komlev@arm.com>
Change-Id: I5b6053aa15228c2f147d17c7bd04059eee9ec720
diff --git a/docs/contributing/index.rst b/docs/contributing/index.rst
index 71ba543..35cc7f6 100644
--- a/docs/contributing/index.rst
+++ b/docs/contributing/index.rst
@@ -8,6 +8,7 @@
     The process <contributing_process>
     Code review <code_review_guide>
     Maintainers and Owners <maintainers>
+    issue_tracking
     coding_guide
     Documentation <doc_guidelines>
     Design proposal <tfm_design_proposal_guideline>