We load another schema, https://diaspora.github.io/diaspora_federation/schemas/federation_entities.json,
that has overlapping definitions, namely #/definitions/post. When the definition from that schema is accessed
first, the json-schema gem caches it and is not smart enough to give precedence to the definition
within the schema document that contains the reference. So for now we have to disambiguate the references
likes this
This commit introduces changes to the user data export archive format.
This extends data set which is included in the archive. This data can be
then imported to other pods when this feature is implemented.
Also the commit adds the archive format json schema. ATM it is used in
automatic tests only, but in future it will also be used to validate
incoming archives.
