add default value to parameter in server connector

devops-client/bin/devops

@@ -1,6 +1,7 @@
 #!/usr/bin/env ruby
 
 require 'rubygems'
-require 'devops-client'
+require 'bundler'
+Bundler.require(:default, :development)
 
 DevopsClient.run

devops-service/db/mongo/connectors/server.rb

@@ -8,7 +8,7 @@ module Connectors
       self.collection = db.collection('servers')
     end
 
-    def servers_find(query, fields)
+    def servers_find(query, fields=nil)
       query_options = fields.nil? ? {} : {fields: fields}
       list(query, query_options)
     end