How to upload images directly to VKontakte?

Question

Ruby on Rails

I host my apps on heroku so there is no way to write to the file system.
Interested in the trail. question: how can I upload images directly to VKontakte?
To work with the API I use the following. gem: https://github.com/7even/vkontakte_api
Before that, it worked through a very strange cycle: the download goes to the server with the site, the image is sent to VK, and then the tasks clean the upload folder every day.
Also, there is a trace. gem: https://github.com/janko-m/paperclip-dropbox
Which is exactly what works directly with dropbox.