Hello, I'm getting the following output when running the specs: ``` Could not load the ruby-graphiz or active_support gems for rendering: cannot load such file -- ruby-graphviz ``` This change (https://github.com/geekq/workflow/commit/3f0c4bb9e1c5fc9e18b122ee86a1aa67490b0cbf#diff-28d45968cd6c27b76bdd91f787ade161) adds a warning every time `ruby-graphviz` cannot be loaded. Is it possible to skip this warning since it is optional? Quoting: > Important: If you're interested in graphing your workflow state machine, you will also need to install the activesupport and ruby-graphviz gems. Thanks!