Added new API for getting Member (aka Users but for use in FE). User is just used for login/registering.

API/Extensions/ClaimsPrincipalExtensions.cs

@@ -0,0 +1,12 @@
+using System.Security.Claims;
+
+namespace API.Extensions
+{
+    public static class ClaimsPrincipalExtensions
+    {
+        public static string GetUsername(this ClaimsPrincipal user)
+        {
+            return user.FindFirst(ClaimTypes.NameIdentifier)?.Value;
+        }
+    }
+}