db.json

{
  "customers":[
    {
      "id": 1,
      "firstName": "Θανάσης",
      "lastName": "Ιωαννίδης",
      "afm": "0123456789",
      "doy": "Ν. ΣΜΥΡΝΗΣ",
      "registeredAt": "2019-08-22T14:15:44+03:00"
    },
    {
      "id": 2,
      "firstName": "Γεωργιος",
      "lastName": "Πετρουλάκος",
      "afm": "9876543210",
      "doy": "ΙΖ ΑΘΗΝΩΝ",
      "registeredAt": "2019-08-23T08:17:03+03:00"
    }
  ],
  "contacts":[
    {
      "id": 1,
      "customerId": 1,
      "firstName": "Μαρία",
      "lastName": "Μαρκοπούλου",
      "registeredAt": "2019-08-22T15:00:00+03:00"
    },
    {
      "id": 2,
      "customerId": 1,
      "firstName": "Κωνσταντίνος",
      "lastName": "Κατακουζινός",
      "registeredAt": "2019-08-22T15:17:02+03:00"
    },
    {
      "id": 3,
      "customerId": 2,
      "firstName": "Ελένη",
      "lastName": "Βλαχάκη",
      "registeredAt": "2019-08-23T10:13:09+03:00"
    }
  ]
}