Add firefox, selenium and gecko driver mapping

Changes:
    - Documentation changes

Tested:
    - NA

Change-Id: I6788416d424781e75430d48f1d9b5680dd0105af
Signed-off-by: George Keishing <gkeishin@in.ibm.com>
diff --git a/docs/gui_setup_reference.md b/docs/gui_setup_reference.md
index 08111c4..b500665 100644
--- a/docs/gui_setup_reference.md
+++ b/docs/gui_setup_reference.md
@@ -47,3 +47,9 @@
     pip install --upgrade xvfbwrapper
     pip install --upgrade robotframework-xvfb
 ```
+
+## Geckodriver Supported Platforms
+
+Mapping between geckodriver releases, and required versions of Selenium and
+Firefox:
+[Geckodriver Supported platforms](https://firefox-source-docs.mozilla.org/testing/geckodriver/Support.html#supported-platforms)