hotfix: career condition on new inserts for users in organizations, and possible duplicates on every collection

[tomassasovsky]

This should be fixed by implementing schema validation for the collections and creating a unique index where fitting.

see mongo-dart/mongo_dart#282 and mongo-dart/mongo_dart#283 for some guidance.

[tomassasovsky]

This keeps happening with clock ins. the current idea is to have a queue per user that's limited to one parallel process.

[NazarenoCavazzon]

@tomassasovsky isn't this done?