More often than not when developing an application you need some sort of data. This can be achieved in many ways, but a quick simple way to do so is by using the json-server library which can be found here.
Create a db.json file and add some data like the example below.
/db.json
{
"users": [
{"id": "23", "firstName": "Fred", "age":32},
{"id": "47", "firstName": "Wilma", "age":31},
{"id": "66", "firstName": "Dino", "age":56},
{"id": "98", "firstName": "BamBam", "age":1}
]
}