I tried to follow the PluginTutorial page and found some oopsies.. I hope the following remarks are welcome and here is the right place for that, as there's no "discussion" page directly linked to this wiki page.
1. The Generating a controller section mentions "You should see the 2 polls and you should be able to vote for them:" but they were not created before, if I'm not wrong. You may suggest to create them just after the model creation, by adding the following lines in the migration before the db:migrate :
Poll.create(:question => "Can you see this poll ?")
Poll.create(:question => "And can you see this other poll ?")
2. I also added a "if poll.save" after the "flash" notice in order to save the poll, otherwise it did not seem to be saved at all, even in production mode.
Moreover, there's a little typo error in the controller : "poll.vote(params[:anwser])" should be replaced by "poll.vote(params[:answer])", or "No" will be incremented in any case ;-)
3. Another little suggestion, but you may disagree : in the beginning it is said to edit "vendor/plugins/redmine_polls/app/blablabla" but next it's said to edit "app/blabla" directly. Maybe it would be a good idea to explicit that all the files related to a plugin are in "vendor/plugins/<plugin_name>" and that "main installation" should not be modified.
4. In Extending the project menu section, templates and controller may be modified in order to keep "project_id" parameter : even if poll are still not project-linked in the database, it would avoid some error pages...
Anyway, I found this tutorial very useful to understand how plugins work, as I'm just a beginner in writing plugins for your great app. See you ... soon :-)