This is a longterm project, but the first task would be to read a csv file and compare the data with a database.
The differences should be listed on a table.
It is a really simple table, so nothing special needed.
If there are new entries => save them to the database
if there are removed entries => also remove them from the database
If the entry has been changed => update the adtabase
This would be a first task, the client will ask for new features every now and then.