The "redirectURLs" field in the client metadata has been updated
to the correct "redirect_uris". To allow backwards compatibility
use Postgres' JSON features to update the actual JSON in the text
field.
json_build_object was introduced in Postgres 9.4. So update the
documentations to require at least this version.
This enables us to control the length of the bytes that will be bcrypted,
by default it's 64.
Also changed the token's stored form from string('text') to []byte('bytea')
and added some test cases for different types of invalid tokens.
