implemented basic crud logic; NB: CONNECTION STRING IN PROGRAM.CS IS EMPTY

Backend.Api/Data/Services/VehicleService.cs

@@ -0,0 +1,45 @@
+namespace Backend.Api.Data.Services
+{
+    public class VehicleService
+    {
+        private readonly DataContext _context;
+        public VehicleService(DataContext context)
+        {
+            _context = context;
+        }
+
+        public void Add(Vehicle vehicle)
+        {
+            _context.Vehicles.Add(vehicle);
+            _context.SaveChanges();
+        }
+
+        public void Remove(long id)
+        {
+            var vehicle = _context.Vehicles.FirstOrDefault(x => x.Id == id);
+            if (vehicle != null)
+            {
+                _context.Vehicles.Remove(vehicle);
+                _context.SaveChanges();
+            }
+        }
+        
+        public void Update(long id, Vehicle newVehicle)
+        {
+            var oldVehicle = _context.Vehicles.FirstOrDefault(x => x.Id == id);
+            oldVehicle = newVehicle;
+            _context.SaveChanges();
+        }
+
+        public Vehicle? Get(long id)
+        {
+            var vehicle = _context.Vehicles.FirstOrDefault(x => x.Id == id);
+            return vehicle;
+        }
+        public User? GetOwner(long id)
+        {
+            var ownerId = _context.Vehicles.FirstOrDefault(x => x.Id == id).OwnerId;
+            return _context.Users.FirstOrDefault(x => x.Id == ownerId);
+        }
+
+    }