added more question variants

SurveyLib.Core/Models/AnswerVariant.cs

@@ -0,0 +1,10 @@
+namespace SurveyLib.Core.Models;
+
+public class AnswerVariant
+{
+    public int Id { get; set; }
+    public int QuestionId { get; set; }
+    public string Text { get; set; }
+
+    public QuestionBase Question { get; set; }
+}

SurveyLib.Core/Models/MultipleAnswerQuestion.cs

@@ -0,0 +1,6 @@
+namespace SurveyLib.Core.Models;
+
+public class MultipleAnswerQuestion : QuestionBase
+{
+    public ICollection<AnswerVariant> AnswerVariants { get; set; }
+}

SurveyLib.Core/Models/QuestionBase.cs

@@ -6,6 +6,8 @@ public class QuestionBase
     public int SurveyId { get; set; }
     public string Title { get; set; }
 
+    public string Discriminator { get; set; }
+
     public Survey Survey { get; set; }
     public ICollection<Answer> Answers { get; set; }
 }

SurveyLib.Core/Models/SingleAnswerQuestion.cs

@@ -0,0 +1,6 @@
+namespace SurveyLib.Core.Models;
+
+public class SingleAnswerQuestion : QuestionBase
+{
+    public ICollection<AnswerVariant> AnswerVariants { get; set; }
+}

SurveyLib.Core/Models/TextQuestion.cs

@@ -0,0 +1,5 @@
+namespace SurveyLib.Core.Models;
+
+public class TextQuestion : QuestionBase
+{
+}