I'm a TA for a professor and he'd like me to scan PDF files and import them into his zotero library. However, as far as I understand Zotero, PDF files and attachments are stored locally on a single users hard drive. I can access his zotero library online (i.e. multiple computers), however, I can't open any of his attachments (which are stored locally on his personal computer). I looked around FAQ and wasn't able to find out whether Zotero had this function already or not, but is there any way to store PDF's and other Zotero attachments on a cloud or other virtual location which can be accessed by users across multiple computers?