[FFM-3363]: Update default config options in docs (harness#85)

Author: Dave Johnston

docs/further_reading.md

@@ -2,6 +2,40 @@
 
 Covers advanced topics (different config options and scenarios)
 
+## Configuration Options
+The following configuration options are available to control the behaviour of the SDK.
+You can provide options by passing them in when the client is created e.g.
+
+```golang
+// Create Options
+client, err := harness.NewCfClient(myApiKey, 
+	harness.WithURL("https://config.ff.harness.io/api/1.0"), 
+	harness.WithEventsURL("https://events.ff.harness.io/api/1.0"), 
+	harness.WithPullInterval(1),
+	harness.WithStreamEnabled(false))
+
+```
+
+| Name            | Config Option                                                  | Description                                                                                                                                      | default                              |
+|-----------------|----------------------------------------------------------------|--------------------------------------------------------------------------------------------------------------------------------------------------|--------------------------------------|
+| baseUrl         | harness.WithURL("https://config.ff.harness.io/api/1.0")        | the URL used to fetch feature flag evaluations. You should change this when using the Feature Flag proxy to http://localhost:7000                | https://config.ff.harness.io/api/1.0 |
+| eventsUrl       | harness.WithEventsURL("https://events.ff.harness.io/api/1.0"), | the URL used to post metrics data to the feature flag service. You should change this when using the Feature Flag proxy to http://localhost:7000 | https://events.ff.harness.io/api/1.0 |
+| pollInterval    | harness.WithPullInterval(1))                                   | when running in stream mode, the interval in minutes that we poll for changes.                                                                   | 60                                   |
+| enableStream    | harness.WithStreamEnabled(false),                              | Enable streaming mode.                                                                                                                           | true                                 |
+| enableAnalytics | *Not Supported*                                                | Enable analytics.  Metrics data is posted every 60s                                                                                              | *Not Supported*                      |
+
+## Logging Configuration
+You can provide your own logger to the SDK, passing it in as a config option.
+The following example creates an instance of the logrus logger and provides it as an option.
+
+
+```golang
+logger := logrus.New()
+
+// Create a feature flag client
+client, err := harness.NewCfClient(myApiKey, harness.WithLogger(logger))
+```
+
 ## Recommended reading
 
 [Feature Flag Concepts](https://ngdocs.harness.io/article/7n9433hkc0-cf-feature-flag-overview)