append method about data-catalog

[andersy005]

I hadn't considered it but it sounds useful and easy to do. It would be a matter of concatenating two or more data frames, removing the duplicate, finally returning a new object.

[matt-long]

Aspects of the technical solution here may be related to the notion of having multiple catalogs versus just one. A concatenate method would enable building collections at different times and appending them a master catalog. We would need a collection field to ensure unique experiment names.

I may also be possible to generate a combined virtual catalog from "system maintained" resources and user defined input.