fix to migration for postgresql

need to detect the adaptor and handle the conversion slightly different for postgres is it requires a USING clause to tell it how to
do the conversion
fixes for postgres migrations

the postgres adaptor has select as a private method, so needed adapting to use select_rows instead
and handle the result as an array rather than a hash.
further fix to the doi action migration

cannot test the instance of the adapter is postgreq, as the class will not be loaded if using a different database
changed to test the class by name