Use the correct port when 0 is passed

lib/thin/backends/tcp_server.rb

@@ -4,26 +4,31 @@ module Backends
     class TcpServer < Base
       # Address and port on which the server is listening for connections.
       attr_accessor :host, :port
-      
+
       def initialize(host, port)
         @host = host
         @port = port
         super()
       end
-      
+
       # Connect the server
       def connect
         @signature = EventMachine.start_server(@host, @port, Connection, &method(:initialize_connection))
+        binary_name = EventMachine.get_sockname( @signature )
+        port_name = Socket.unpack_sockaddr_in( binary_name )
+        @port = port_name[0]
+        @host = port_name[1]
+        @signature
       end
-      
+
       # Stops the server
       def disconnect
         EventMachine.stop_server(@signature)
       end
-            
+
       def to_s
         "#{@host}:#{@port}"
       end
     end
   end
-end
+end