Create an ergonomic way to handle manual data

[UlisesGascon]

This issue is related to #52. As I user I wan to be able to add training information to the database, but in the future we might have similar scenarios. Ideally we can do this from the CLI or a better interface.

[UlisesGascon]

After a great discussion with @inigomarquinez, seems like the best approach will be to support the bulk introduction of changes from the input collected with the forms that @ruddermann is building.

We can work on a POC as soon as @ruddermann has a basic form.