A complete web application built from scratch - open to bidding

We are looking for a developer (or developers) on a longterm basis. The web application will need continuously improvement and adding new features. Basic project details: Build up an entire closed web application from scratch, but using pre-made UI based on Bootstrap and responsive design. It will be a system containing different types of modules and access levels. Basically the access levels will look something like this: System administrators (us) - Partner 1 -- Customer --- CEO ---- Officer ----- Employee - Partner 2 -- Customer --- CEO ---- Officer ----- Employee And so on ... Customers will also be connected to one or more specific categories for option to edit/share/send message to many customers at once. Front-end for CEO/Officer/Employee with access levels in each Customer (with login) Back-end for system administrator and partners with access levels (with login) Some of the desired features are: - Document sharing between partners and their customers - Messaging system - E-mail notification and inside application notification on changes/updates/messages/documents shared - Risk calculation system with forms on specific type of work (likeliness multiplied with consequence) and a graphic feedback on result. - Report incidents via form with notifications to CEO / Officer / Partner - Future API integrations to existing CRM systems etc. As for UI, Bootstrap and responsive design are requirements. We would like the developer to use a pre-made framework based on Bootstrap, like this for example: [login to view URL] As for language/frameworks, we are open for suggestions from developers. PHP and MySQL maybe?