Merge pull request #2 from calh/nil_shard_config

Check that @config exists.  Fixes thiagopradi#413

Author: calh

lib/octopus/abstract_adapter.rb

@@ -19,7 +19,7 @@ def method_missing(meth, *args, &block)
       end
 
       def octopus_shard
-        @config[:octopus_shard]
+        @config && @config[:octopus_shard]
       end
 
       def initialize(*args)