added release-0.5.0

Can you highlight the benefit of taking the `<paper-input-decorator>` approach vs. just using `<paper-input>`? From reading this post, I'm not sure why I would want to do that.

Also, in your example, `<input type="someType">` implies that I could use `<paper-input-decorator>` to wrap *any* [input type](https://developer.mozilla.org/en-US/docs/Web/HTML/Element/Input#attr-type). I'm assuming that's not the case, and this is only meant for text-like inputs?