building the example widget

[Sandro Montanari]

hi,

i'm following the guide on github to implement an example widget.
Unfortunately i'm running into an error, i can't resolve:

> Dashboard.find(1).widgets.create!(:name => "test", :kind => "example")

  Dashboard Load (0.2ms)  SELECT "dashboards".* FROM "dashboards" WHERE "dashboards"."id" = ? LIMIT 1  [["id", 1]]
   (0.1ms)  begin transaction
   (0.1ms)  rollback transaction
TypeError: no implicit conversion from nil to integer
    from /home/tgdmosaa/development/workspace/team_dashboard/app/models/widget.rb:42:in `fetch'
    from /home/tgdmosaa/development/workspace/team_dashboard/app/models/widget.rb:42:in `validate_source_attributes'
...

same thing if i try to add it in the gui.

can you help me please?

thanks!