Update README for new sets

modules/islandora_oaipmh/README.md

@@ -1,28 +1,38 @@
 # Islandora OAI-PMH Endpoint
 
-This submodule leverages the [rest\_oai\_pmh module](https://www.drupal.org/project/rest_oai_pmh)
-to provide an OAI-PMH endpoint to allow harvesting repository content.
-
-By default the OAI-PMH endpoint is located at 'yoursite.example/oai/request'
-and includes a set identified as 'oai\_pmh:all\_repository\_items' which can be
-further configured by editing the provided OAI-PMH view. The provided set 
-includes all items using the 'repository item' content type that _don't_ use 
-the 'Collection' model. Additional sets can be created by making views with the
-Entity Reference view display mode and enabling them on the rest\_oai\_pmh
+This submodule leverages the [REST OAI-PMH module](https://www.drupal.org/project/rest_oai_pmh)
+to provide an OAI-PMH endpoint for harvesting repository content.
+
+## Sets available
+
+By default the OAI-PMH endpoint is located at 'yoursite.example/oai/request'.
+It contains (when queried with `?verb=ListSets`) one Set representing each
+Collection in the repository containing all the children of that collection,
+and a Set containing all Repository Items that are not members of collections
+(and are not Collections themselves). Included, but disabled by default, is
+a set identified as 'oai\_pmh:all\_repository\_items'. It includes
+all items using the 'Repository item' content type that _don't_ use 
+the 'Collection' model. Additional sets can be created by making Views with the
+"Entity Reference" View display mode and enabling them on the rest\_oai\_pmh
 configuration page: `/admin/config/services/rest/oai-pmh`. The module can use
 any view using an Entity Reference view display mode, they do not need to be
-part of the provided OAI-PMH view, it is simply available as a convenience.
+part of the provided OAI-PMH views, they are simply available as a convenience.
 
 The rest\_oai\_pmh module indexes set membership, so repository items may not appear
 immediately in their respective sets. Indexing will happen automatically during
 cron runs but can be triggered manually at `/admin/config/services/rest/oai-pmh/queue`.
 
-This module uses the Dublin Core metadata defined by
-the [repository item content model's RDF mapping](http://islandora.github.io/documentation/user-documentation/content_types/#update-create-an-rdf-mapping).
-However, the RDF mapping does not include support for islandora\_default's use
-of the linked agent field. Including agent links in the OAI-PMH metadata
+## Mappings
+
+The REST OAI PMH module expects Dublin Core metadata to be made available
+either through the RDF module or the Metatag module. By default, this module
+uses the [Repository Item content model's RDF mapping](http://islandora.github.io/documentation/user-documentation/content_types/#update-create-an-rdf-mapping).
+However, the default RDF mapping for the Linked Agent field is not Dublin 
+Core so is not supported by REST OAI PMH. 
+
+Including agent links in the OAI-PMH metadata
 currently requires updating the RDF mapping to include a Dublin Core predicate
-for that field or any other additional fields. Alternatively, the rest\_oai\_pmh module 
+for that field or any other additional Typed Relation fields. Alternatively, the `rest_oai_pmh` module 
 also supports defining mappings with the
 [metatag module](https://www.drupal.org/project/metatag) or creating a custom
 OaiMetadataMap plugin.
@@ -34,4 +44,4 @@ OaiMetadataMap plugin.
 1. Trigger the OAI-PMH indexer: Click the button found on the page at `http://localhost:8000/admin/config/services/rest/oai-pmh/queue` (or wait for cron)
 1. Give anonymous users the "Access GET on OAI-PMH resource" permission.
 
-Your OAI-PMH Endpoint should now be ready. e.g. `http://localhost:8000/oai/request?verb=ListRecords&metadataPrefix=oai\_dc`
+Your OAI-PMH Endpoint should now be ready. e.g. `http://localhost:8000/oai/request?verb=ListRecords&metadataPrefix=oai_dc`