Sensible way to add multiple publications

[NickCEBM]

Right now we will remove a preprint in favour of a full publication, but it would be good to be able to track full publication timelines.

[NickCEBM]

At the moment, I'm inclined to do a column structure that looks something like:

preprint_pub preprint_pub_date journal_pub journal_pub_date other_publications

The preprint/journal pub fields would link to the first instance (or most complete instance) of a publication related to that trial, and the other publications would be a list of additional publication DOIs.