Catch potential failure to parse json
Postpone download if database is too busy.
Create uniq index for doc collection id field
Remove logging
Make insert continue on duplicate keys and ignore error
Create object to read next file on demand
DocHelper.drainHostDocReader will insert into db docs from HostDocReader
Promise unit test
Added byline and when
call doBookkeeping after flush and db insert promises are resolved
Fixed download tunr off/on logic in the script
Make download read commands file and stop on demand