Yesterday I've written a module for myself. Just an experiment. When I was feeling satisfied, I've created a repository on github, and pushed my code. My module and yii are on github. So I'll show you a "new" way to start our yii projects.
Uploading files in a webapp can be extremely tricky and sometimes the quickest way to do it is to store the file directly in the webserver or into a DNS (like Amazon S3) and then to save the link and the metadata inside a table in the DB. The thing is that you'll have to deal with file permissions, server storage, file management and so on (which is perfectly fine, by the way).