Gather offers you the ability to add statuses unique to your workflow.
From the "Account" dropdown in the upper right corner of your account click on "Settings".
Select the "Statuses" tab.
Gather starts you out with 9 default statuses. 3 of these, shown below, cannot be edited or deleted as they are tied into the system.
The remaining 6 can be renamed by clicking on the pencil icon or deleted by clicking the trash icon.
To add more custom statuses simply click "Add Statuses" and enter in a name.
Statuses can be reordered by clicking on the 2 lines and dragging the status up or down into position.
To learn more about Custom Statuses, check out this video