GitHub: add issue template to inform users

Inform users that keeping on reporting problems on GitHub
is not helpful and, instead, redirect them to the Gerrit Issue Tracker.

Change-Id: If4ddefc33d6979eb9dc31e93507db187fe372e36
diff --git a/.github/ISSUE_TEMPLATE/raising-issues.md b/.github/ISSUE_TEMPLATE/raising-issues.md
new file mode 100644
index 0000000..b620214
--- /dev/null
+++ b/.github/ISSUE_TEMPLATE/raising-issues.md
@@ -0,0 +1,14 @@
+---
+name: Raising issues
+about: Important Notice on how to raise issues
+title: ''
+labels: ''
+assignees: ''
+
+---
+
+Issues submission is done through [Gerrit Issue Tracker](https://bugs.chromium.org/p/gerrit/issues/list).
+Unfortunately, we cannot accept or follow-up issues raised on GitHub.
+This is a read-only project replica and is not monitored on a regular basis.
+
+Thank you in advance for your understanding.