save mappings in loom
set of calls to create mapping and mapping terms. It uses redis cache to speed up the process.
respond_to?run -->  respond_to?:run
redis client as a instance variable in module Mappings::Batch
note to revise these mapping methods that are probably obsolote
isolation of id generation in mappings and term mapping to be used in cache (redis). It helps to not create models when it is not really needed.
mappings can exist without a process.
delete mappings/term mapping also removes cache entries.
missing end
half way to finish loom testing. tedious.