Added endpoint for registering a user locally after successful logon from Auth0

YABA.API/Controllers/UsersController.cs

@@ -0,0 +1,40 @@
+using Microsoft.AspNetCore.Authorization;
+using Microsoft.AspNetCore.Http;
+using Microsoft.AspNetCore.Mvc;
+using System.Net;
+using YABA.API.Extensions;
+using YABA.API.ViewModels;
+using YABA.Service.Interfaces;
+
+namespace YABA.API.Controllers
+{
+    [ApiVersion("1")]
+    [Authorize, Route("api/v{version:apiVersion}/[controller]")]
+    public class UsersController : ControllerBase
+    {
+        private readonly IUserService _userService;
+
+        public UsersController(IUserService userService)
+        {
+            _userService = userService;
+        }
+
+        [HttpPost("Register")]
+        [ProducesResponseType(typeof(UserResponse), (int)HttpStatusCode.OK)]
+        [ProducesResponseType((int)HttpStatusCode.NotFound)]
+        [ProducesResponseType((int)HttpStatusCode.NoContent)]
+        public IActionResult Register()
+        {
+            var authProviderId = this.GetAuthProviderId();
+
+            if (string.IsNullOrEmpty(authProviderId)) return NotFound();
+
+            var isRegistered = _userService.IsUserRegistered(authProviderId);
+
+            if (isRegistered) return NoContent();
+
+            var registedUser = _userService.RegisterUser(authProviderId);
+            return Ok(new UserResponse(registedUser));
+        }
+    }
+}