Register MIME-type with IANA

[adamvoss]

Maybe this is planned or premature, but figure I would report it since it came up in researching json-schema-org/json-schema-org.github.io#31 / json-schema-org/json-schema-org.github.io#32.

I notice that "application/schema+json" (which is specified in the standard) does not appear in mime-db as a known schema. That project indicates the recommended way to add it there is to register it with IANA, and since JSON Schema already has an Internet Draft it does not seem like it may not be too difficult to register it..

I checked the IANA registry just to be sure, and it was not there.

[handrews]

@vossad01 I don't think we're quite at that point yet. I don't know if we need to be in RFC for that, but I suspect we should at least have reached working group status before submitting it.

Also, there are a number of media type details that are still being worked out, e.g. #222.

[handrews]

Per RFC §4.10, a standards-tree media type MUST be published in an an RFC. This will be a natural part of getting JSON Schema to RFC and we don't need a separate issue to track it.