This is a new workflow that allows you to delete duplicate entries in Contour. It works on a last in, first out basis (LIFO). I use it for things like alert signup forms on sites where there's no membership, so that you can re-submit the form and change your preferences.
To use it, install the package, and when you add a new workflow in Contour, you will have the option to select "remove duplicate entries". Select the workflow, and then specify one or more fields that you want to use to check for duplicates (in my case, I was using an email address field). All of the fields entered must be identical in order to trigger the workflow.
When a record is entered, the workflow checks for duplicates, and deletes the older records, only keeping the one that was just submitted. Any delete workflows are not trigered by the deletion of the older records.