To use program properly you need create database.json file with structure like below
{
"sourceConfig": {
"connectionString": "Host=<hostname>;Port=5432;Password=<password>;Username=<username>;Database=<db name>"
},
"hostConfig": {
"connectionString": "Host=<hostname>;Port=5432;Password=<password>;Username=<username>;Database=<db name>"
}
}