Added validation and fixed errors

SchengenVisaApi/ApplicationLayer/Services/Users/IUsersService.cs

@@ -0,0 +1,23 @@
+using ApplicationLayer.Services.Users.Requests;
+using Domains.Users;
+
+namespace ApplicationLayer.Services.Users
+{
+    /// user accounts service
+    public interface IUsersService
+    {
+        /// Returns all user accounts with role of approving authority
+        /// <param name="cancellationToken">Cancellation token</param>
+        Task<List<User>> GetAuthoritiesAccountsAsync(CancellationToken cancellationToken);
+
+        /// Changes authentication data for an account
+        /// <param name="request"> Request object with identifier of user and new authentication data</param>
+        /// <param name="cancellationToken">Cancellation token</param>
+        Task ChangeAccountAuthDataAsync(ChangeUserAuthDataRequest request, CancellationToken cancellationToken);
+
+        /// Removes user account
+        /// <param name="userId">Identifier of account</param>
+        /// <param name="cancellationToken">Cancellation token</param>
+        Task RemoveUserAccount(Guid userId, CancellationToken cancellationToken);
+    }
+}