[fix] create uploads folder and permissions

[Rafi594]

• Fix #26. When uploading a file to a repository from web interface, a temporary folder is used on /opt/gogs/data wich needs gogs permissions.

[M5oul]

What does it fix? Could you explain why did you do that.

[Rafi594]

fix issue #26

[M5oul]

How do you upload files?

[Rafi594]

With the web interface

[M5oul]

Ok, to upload a file to a repository. Tested. It works fine.

[M5oul]

Thanks for this fix. I let three days to @mbugeia to review it. Otherwire, I will merge it.