Adding TKey support

MongoDbGenericRepository/Models/IDocument.cs

@@ -6,16 +6,24 @@ namespace MongoDbGenericRepository.Models
     /// This class represents a basic document that can be stored in MongoDb.
     /// Your document must implement this class in order for the MongoDbRepository to handle them.
     /// </summary>
-    public interface IDocument
+    public interface IDocument<TKey> where TKey : IEquatable<TKey>
     {
         /// <summary>
         /// The Guid, which must be decorated with the [BsonId] attribute 
         /// if you want the MongoDb C# driver to consider it to be the document ID.
         /// </summary>
-        Guid Id { get; set; }
+        TKey Id { get; set; }
         /// <summary>
         /// A version number, to indicate the version of the schema.
         /// </summary>
         int Version { get; set; }
     }
+
+    /// <summary>
+    /// This class represents a basic document that can be stored in MongoDb.
+    /// Your document must implement this class in order for the MongoDbRepository to handle them.
+    /// </summary>
+    public interface IDocument: IDocument<Guid>
+    {
+    }
 }