Issue #9 in Mini-RFC

[golnazads]

Re-importing references should be an idempotent operation for sources that have not been modified, i.e. if I upload the same reference file in the DB, and none of the reference strings have changed, we don’t want to wipe away the resolved results (unless we explicitly force this via a command line argument). Similarly, if just one of the references has been modified, this will be the only reference that will be re-resolved, while all the unchanged records will remain as they are. In order to deal with the updating and deletion of records that are no longer present in the source file we could simply track the status of each reference via a flag (PENDING, PROCESSED, DELETED).

Explanation
Check single reference string at a time and run only if the reference string has changed.

[aaccomazzi]

@ehenneken please review and provide feedback

[ehenneken]

@golnazads @aaccomazzi agreed