add term relationshipAccordingToID to Resource Relationship extension

[jhpoelen]

Suggest to add relationshipAccordingToID to Resource Relation extension to help link human readable text (e.g., some citation) to a machine readable identifier (e.g., some doi) .

For discussion see trias-project/uredinales-belgium-checklist#8 (comment) .

[tucotuco]

Though it would be easy, as the management of extensions is quite loose and not a standards-based process, I would not just add the term to the extension - I would add it to Darwin Core.

I created an issue to make a task group to clarify and document the process of making an extension into a standard (see #188).

[peterdesmet]

This proposal needs more evidence for demand (see the Vocabulary Maintenance Specification - Section 3.1). Anybody who is interested in the adoption/change of this term, should comment with their use case below. If demand is not demonstrated by the next annual review of open proposals (late 2020), this proposal will be dismissed.

@jhpoelen note that #186 will be submitted for public review.

[jhpoelen]

@peterdesmet excellent - thanks for the update. I hope that #186 (once approved) will be sufficient to get more folks to use Resource Relationship extension for species interactions.