Add latest change note field to schema
Merge pull request #306 from alphagov/add-latest-change-note-field-to-schema

Add latest change note field to schema
Helpful error for unconfigured document types

Previously this was giving:
NoMethodError - undefined method `[]' for nil:NilClass:
	/var/govuk/rummager/lib/document.rb:16:in `from_hash'
Merge pull request #307 from alphagov/helpful_error_on_unconfigured_types

Helpful error for unconfigured document types