Management App simplifies the coordination between the various contractors working together on our projects

we want to make a app that simplyfies the workflow on the jobs that we have. The app have to have Projects unets (name) below the project, there should be folegend functions - To-do lists/checklists - Share project information and plans - upload pdf files , can be view in the app - View and update the projects todo-list ( The to-do list can be directed to the group as well as specific members of the group.) - Message other contractors working on the projects (like message on facebook groop chat) - Upload photos of work and view project gallery ( the pictures that the people upload in the group chat shod be uplodet to this folder as well. Admin panel can create new projects and decide who can access the different projects. create new users and delete/look old users Use templets/copy old make to-do list/checklists a place where you can see all the conversations on the projects The most important thing about the app is that it should be easy and use. lightweight design. The app should be for iphone and android as short production time as possible, startup as soon as possible. If you do not have the skills available, please do not answer. Thanks for all the answers I get