Gem or fast way to build task management system


I have built a platform connecting business consultants and information
purchasers online using Ruby on Rails.

I wondering if there is any Gem to implement a task management service
business consultants, which is similar to basic version of Enterprise
Resource Planning (ERP) system. A few examples of such features would
include: registering client info, client case upload, client case status
check, consulting service fee calculation, schedule check with calendar
function, and other eDocs system.

If there is no such gem, can anyone recommend me a fast way to implement
such system?

Thank you!