Better error checking for new ideas.

You can't get away with submitting ideas without a name anymore. This code also needs to be tested, but I'm being lazy and want to get moving on other stuff.
Update to the latest, less buggy version of puma (2.1.0).
Only assign an id to an Idea right before it's about to be saved.

This prevents Rails putting it in the url when double errors occur.
Add user logins/signups etc. from devise and add them to ideas.