Fix FAB-417 - missing info on setting up SSH key

Add instructions to clarify use of LFID for all tools
and ensure that info on setting up your SSH public key
in Gerrit is prominent in CONTRIBUTING.md

Change-Id: I04ec5d549350137724bcc5b45cb953bca4da4b1e
Signed-off-by: Christopher Ferris <chris.ferris@gmail.com>

docs/CONTRIBUTING.md

@@ -10,8 +10,18 @@ before participating. It is important that we keep things civil.
 ## Getting a Linux Foundation account
 
 In order to participate in the development of the Hyperledger Fabric project,
-you will need an [LF account](Gerrit/lf-account.md). This will give you single
-sign-on to all the community tools, including Gerrit and Jira (coming soon!).
+you will need an [LF account](Gerrit/lf-account.md). You will need to use
+your LF ID to grant you access to all the Hyperledger community tools, including
+[Gerrit](https://gerrit.hyperledger.org) and [Jira](https://jira.hyperledger.org).
+
+### Setting up your SSH key
+
+For Gerrit, you will want to register your public SSH key. Login to
+[Gerrit](https://gerrit.hyperledger.org)
+with your LF account, and click on your name in the upper right-hand corner
+and then click 'Settings'. In the left-hand margin, you should see a link for
+'SSH Public Keys'. Copy-n-paste your [public SSH key](https://help.github.com/articles/generating-an-ssh-key/)
+into the window and press 'Add'.
 
 ## Getting help