add field level descriptions and doclink to github webhook

update installGit to fix sampleInput for events, and document "organization/" support
closes #1102
diff --git a/catalog/installGit.sh b/catalog/installGit.sh
index 0fb8b75..ce678fb 100755
--- a/catalog/installGit.sh
+++ b/catalog/installGit.sh
@@ -19,9 +19,9 @@
 install "$CATALOG_HOME/github/webhook.js" \
     github/webhook \
     -a feed true \
-    -a description 'Creates a webhook on github to be notified on selected changes' \
-    -a parameters '[ {"name":"username", "required":true, "bindTime":true}, {"name":"repository", "required":true, "bindTime":true}, {"name":"accessToken", "required":true, "bindTime":true},{"name":"events", "required":true} ]' \
-    -a sampleInput '{"username":"whisk", "repository":"WhiskRepository", "accessToken":"123ABCXYZ", "events": "push,commit,delete"}'
+    -a description 'Creates a webhook on GitHub to be notified on selected changes' \
+    -a parameters '[ {"name":"username", "required":true, "bindTime":true, "description": "Your GitHub username"}, {"name":"repository", "required":true, "bindTime":true, "description": "The name of a GitHub repository"}, {"name":"accessToken", "required":true, "bindTime":true, "description": "A webhook or personal token", "doclink": "https://github.com/settings/tokens/new"},{"name":"events", "required":true, "description": "A comma-separated list", "doclink": "https://developer.github.com/webhooks/#events"} ]' \
+    -a sampleInput '{"username":"myUserName", "repository":"myRepository or myOrganization/myRepository", "accessToken":"123ABCXYZ", "events": "push,delete,pull-request"}'
 
 waitForAll