Update the README with producer usage for the "new way"

Fixes #26

README.md

@@ -4,10 +4,15 @@
 
 A Ruby gem implementing a Kafka Publisher and Consumer
 
-This library wraps the
-[librdkafka library](https://github.com/edenhill/librdkafka) which is
-implemented in C.  This library must be installed before we can use
-the Hermann gem.
+On MRI (C-based Ruby), this library wraps the [librdkafka
+library](https://github.com/edenhill/librdkafka) which is implemented in C.
+
+On JRuby this library [declares jar
+dependencies](https://github.com/mkristian/jar-dependencies/wiki/declare-jars-inside-gemspec)
+inside the `.gemspec` to express dependencies on the Java-based Kafka library
+provided by the Kafka project. Tools like
+[jbundler](https://github.com/mkristian/jbundler) will handle these
+declarations correctly.
 
 ### Usage
 
@@ -20,36 +25,57 @@ straightforward.
 - This is an early alpha version of the gem, so expect bumps in the
   road.
 
-**Note:**  The current implementation needs work to ensure thread safety.
 
-Both Consumers and Producers now hold their own references to their
-Kafka state, and should be able to coexist nicely.
+### Producer
 
-The brokers list and partition specification for Consumers are now
-working, as well.  Producers will detect the number of partitions in a
-topic and randomly spread their messages over the set of partitions.
+#### Zookeeper discovery (JRuby-only)
 
-Consumers currently do not remember their "last message", nor do they
-yet coordinate partition (re)assigment within consumer groups.
+```
+[1] pry(main)> 
+[2] pry(main)> require 'hermann/producer'
+=> true
+[3] pry(main)> require 'hermann/discovery/zookeeper'
+=> true
+[4] pry(main)> p = Hermann::Producer.new('topic', Hermann::Discovery::Zookeeper.new('localhost:2181').get_brokers)
+=> #<Hermann::Producer:0x09e2ad91
+ @brokers="localhost:6667",
+ @children=[],
+ @internal=#<Hermann::Provider::JavaProducer:0x064524dd @producer=#<Java::KafkaJavaapiProducer::Producer:0x79d06bbd>, @topic="topic">,
+ @topic="topic">
+[5] pry(main)> f = p.push('hello world')
+=> #<Concurrent::Promise:0x6c42f2a1
+ @children=[],
+ @event=#<Concurrent::Event:0x17a703f5 @condition=#<Concurrent::Condition:0x5ff2b8ca @condition=#<ConditionVariable:0x618ad2aa>>, @mutex=#<Mutex:0x1aa6e3c0>, @set=false>,
+ @executor=#<Concurrent::ThreadPoolExecutor:0x3531f3ca @executor=#<Java::JavaUtilConcurrent::ThreadPoolExecutor:0x7fcf294e>, @max_queue=30, @overflow_policy=:abort>,
+ @mutex=#<Mutex:0x59e43e8c>,
+ @on_fulfill=#<Proc:0x2caa5d7c@/home/tyler/.rvm/gems/jruby-1.7.15@rubygems/gems/concurrent-ruby-0.7.0-java/lib/concurrent/promise.rb:38>,
+ @on_reject=#<Proc:0x5e671e20@/home/tyler/.rvm/gems/jruby-1.7.15@rubygems/gems/concurrent-ruby-0.7.0-java/lib/concurrent/promise.rb:39>,
+ @parent=nil,
+ @promise_body=#<Proc:0x38fc5554@/usr/home/tyler/source/github/ruby/Hermann/lib/hermann/provider/java_producer.rb:36>,
+ @state=:pending>
+[6] pry(main)> f.value
+=> nil
+[7] pry(main)> f.state
+=> :fulfilled
+[8] pry(main)> 
+```
 
-#### Consumer
 
-    require 'hermann'
+#### MRI only
 
-    # Initialize requires topic, brokers list, and partition number
+```
+[1] pry(main)> require 'hermann/producer'
+=> true
+[2] pry(main)> p = Hermann::Producer.new('topic', 'localhost:6667')
+=> #<Hermann::Producer:0x00000805e05aa8 @brokers="localhost:6667", @children=[], @internal=#<Hermann::Lib::Producer:0x00000805e05a58>, @topic="topic">
+[3] pry(main)> f = p.push('hello world from mri')
+=> #<Hermann::Result:0x00000805ef9b08 @producer=#<Hermann::Producer:0x00000805e05aa8 @brokers="localhost:6667", @children=[#<Hermann::Result:0x00000805ef9b08 ...>], @internal=#<Hermann::Lib::Producer:0x00000805e05a58>, @topic="topic">, @reason=nil, @state=:unfulfilled, @value=nil>
+[4] pry(main)> f.state
+=> :unfulfilled
+[5] pry(main)> p.tick_reactor
+=> 1
+[6] pry(main)> f.state
+=> :fulfilled
+[7] pry(main)> 
 
-    c = Hermann::Consumer.new( "device_actions", "localhost:9092", 0 )
-    c.consume() do
-      |msg| puts("Received: #{msg}")
-    end
-
-#### Producer
-
-    require 'hermann'
-
-    p = Hermann::Producer.new( "device_actions", "localhost:9092" )
-
-    messages = [ "Locate", "Scream", "Wipe", "Degauss" ]
-    messages.each do
-        |msg| p.push(msg)
-    end
+```