write a handler for hash.
raise if required settings don't exist.
alter structure of add_source config.
add required setting.
add tests.
fix overriding of data.
fix source data.
don't allow adding a non-unique source.
add tests.
remove unused test.
make sure exclusions always exists.
don't add sources to source_settings.
add a bunch of rsync stuff.
add more rake tasks for tests.