fix: Addressing PR comments

API/DTOs/Koreader/KoreaderProgressUpdateDto.cs

@@ -4,6 +4,12 @@ namespace API.DTOs.Koreader;
 
 public class KoreaderProgressUpdateDto
 {
+    /// <summary>
+    /// This is the Koreader hash of the book. It is used to identify the book.
+    /// </summary>
     public string Document { get; set; }
+    /// <summary>
+    /// UTC Timestamp to return to KOReader
+    /// </summary>
     public DateTime Timestamp { get; set; }
 }