[FA-17] Update auth

FictionArchive.Service.Shared/Constants/AuthorizationConstants.cs

@@ -0,0 +1,15 @@
+namespace FictionArchive.Service.Shared.Constants;
+
+public static class AuthorizationConstants
+{
+    public static class Roles
+    {
+        public const string Admin = "admin";
+    }
+
+    public static class Policies
+    {
+        public const string Admin = "Admin";
+        public const string User = "User";
+    }
+}