README.md in sidekiq-datadog-0.3.5 vs README.md in sidekiq-datadog-0.4.0

@@ -19,10 +19,48 @@
       config.server_middleware do |chain|
         chain.add Sidekiq::Middleware::Server::Datadog
       end
     end
 
-For full configuration options, please see the [Documentation](http://www.rubydoc.info/gems/sidekiq-datadog).
+## Options
+
+Options can be configured to be passed to the middleware constructor when it is added to the
+chain
+
+    Sidekiq.configure_server do |config|
+      config.server_middleware do |chain|
+        chain.add(Sidekiq::Middleware::Server::Datadog, statsd_port: 3334)
+      end
+    end
+
+Custom tags can be configured using the `tags:` property
+
+    Sidekiq.configure_server do |config|
+      config.server_middleware do |chain|
+        chain.add(Sidekiq::Middleware::Server::Datadog, tags: ['runtime:jruby'])
+      end
+    end
+
+Dynamic tags can be configured by passing a lambda in the tags array. It is
+executed at runtime when the job is processed
+
+    Sidekiq.configure_server do |config|
+      config.server_middleware do |chain|
+        chain.add(Sidekiq::Middleware::Server::Datadog, tags: [->(worker, job, queue, error){
+          "source:#{job['source']}"
+        }])
+      end
+    end
+
+#### supported options
+ - *hostname* - the hostname used for instrumentation, defaults to system hostname. Can also be set with the `INSTRUMENTATION_HOSTNAME` env var.
+ - *metric_name* - the metric name (prefix) to use, defaults to "sidekiq.job".
+ - *tags* - array of custom tags. These can be plain strings or lambda blocks
+ - *statsd_host* - the statsD host, defaults to "localhost". Can also be set with the `STATSD_HOST` env var
+ - *statsd_port* - the statsD port, defaults to 8125. Can also be set with the `STATSD_PORT` env var
+ - *statsd* - custom statsd instance
+
+For more detailed configuration options, please see the [Documentation](http://www.rubydoc.info/gems/sidekiq-datadog).
 
 ## Contributing
 
 1. Fork it
 2. Create your feature branch (`git checkout -b my-new-feature`)