Hey, folks.

I have a team of article writers and I get orders from clients from various sources. I am struggling to manage these article writing assignments.

Currently I use excel spreadsheets, but it is hard to keep track of deadlines and including order-specific information is a pain.

I was wondering if there is a useful content management system to help me in this situation.

The following functionality is all the system needs:
-user (writer) and administrator accounts
-tasks with deadlines
-file attachments

There are many open source project management systems (ProjectPier, PHProjekt, Redmine), but they are more useful for complex situation where projects have multiple tasks.