Consider defining a `URL` type

[mbrush]

There are several fields in the schema that take urls, which are defined using a string data type, and informally described as taking a url. Consider if TRAPI wants to define a dedicated URL type as it does for CURIE- which would allow additional constraint and validation on values.

Also, there is no regex pattern defined for the CURIE type - which could be useful for validation of fields taking curies.

[mbrush]

Not sure there are any use cases for it currently, but a uriorcurie types may also be useful for fields that can take a uri/url or a curie (analogous to the biolink:uriorcurie type

[edeutsch]

There are several fields in the schema that take urls, which are defined using a string data type, and informally described as taking a url. Consider if TRAPI wants to define a dedicated URL type as it does for CURIE- which would allow additional constraint and validation on values.

sounds like a good idea to me. Care to make a PR?

Also, there is no regex pattern defined for the CURIE type - which could be useful for validation of fields taking curies.

sounds good to me. Care to make a PR? I don't know quite what such a regex would look like. I googled around a little and came up with this, but this doesn't seem appropriate:
https://gist.github.com/niklasl/2506955