Add Prometheus metrics and query endpoint

Extend controller with counters to measure activity
Add /a1-p/metrics endpoint to expose measures in Prometheus format
Document new environment variable prometheus_multiproc_dir

Issue-ID: RIC-353
Signed-off-by: Lott, Christopher (cl778h) <cl778h@att.com>
Change-Id: I44bc5346b627b27ba5b344187223dd0323b32a2c
diff --git a/docs/user-guide-api.rst b/docs/user-guide-api.rst
index 2dcd31e..5136d06 100644
--- a/docs/user-guide-api.rst
+++ b/docs/user-guide-api.rst
@@ -4,6 +4,10 @@
 User Guide and APIs
 ===================
 
+.. contents::
+   :depth: 3
+   :local:
+
 This document explains how to communicate with the A1 Mediator.
 Information for maintainers of this platform component is in the Developer Guide.
 
@@ -33,6 +37,12 @@
     }
 
 
+For example, if you put the JSON above into a file called "create.json" you can use
+the curl command-line tool to send the request::
+
+    curl -X PUT --header "Content-Type: application/json" --data-raw @create.json http://localhost/a1-p/policytypes/20008
+
+
 Send the following JSON to create an instance of policy type 20008:
 
 .. code-block:: yaml
@@ -42,6 +52,11 @@
     }
 
 
+For example, you can use the curl command-line tool to send this request::
+
+    curl -X PUT --header "Content-Type: application/json" --data '{"threshold" : 5}' http://localhost/a1-p/policytypes/20008/policies/tsapolicy145
+
+
 Integrating Xapps with A1
 -------------------------