I would like to hire a Software Developer

Webpage is basically a network of users who all own some PDF files. All the PDF files data are stored in the database and webpage can generate particular PDF file on request. Users can filter their PDFs and share them among their friends. If file is shared with user, the amount of data he is able to see are dependant on his user type. Also, rights to view PDF data has only one user at a time. It basically means that once user "shares" file with his friend, he himself loses the access to the file till his friend "shares" the file back. ####Main points to focus on: 1. Layered users structure * Registration * "friend" concept integrated * Various user types (different permissions regarding data access) + tree hierarchy of users 2. Underlying file system assigned to each user * all private data stored in DB layer * option to share data(files - PDFs) among chosen users * filtering based on chosen PDF data fields 3. User can preview his PDF in embedded PDF viewer (PDFs are basically stored just as data in DB layer) or generate and download the file to his local machine. 4. Last but not least! data security and ecryption should be secured. ####Database schema Either left up to developer to create his own one or we can provide the basic table and relations structure. ###Required technologies to use There are **no requirements/restrictions** on technologies used, though we prefer conservative approach of writting code rather than using popular content management systems. Therefore HTML(5), Javascript, CSS and mastered backend language(PHP, RubyOnRails etc) are highly appreciated. Database may also be based on NoSQL concept if the reasoning behind such decision makes sense. Amount of data(PDFs) for particular user types may over time get pretty big so e.g Column Store database could provide a performance boost. We appreciate any suggestions and are ready to learn. We would also appreciate to work with someone who already has some positive recommendations in his resume/account. Thanks!