Added endpoint to create new Contact

Models/Contact.cs

@@ -2,6 +2,7 @@ using System;
 
 using MongoDB.Bson;
 using MongoDB.Bson.Serialization.Attributes;
+using Newtonsoft.Json;
 
 namespace TextSender_API.Models;
 
@@ -10,17 +11,23 @@ public class Contact
 #region Properties
     [BsonId]
     [BsonRepresentation(BsonType.ObjectId)]
+    [JsonProperty("id")]
     public string? Id { get; set; }
     [BsonElement("firstname")]
+    [JsonProperty("firstname")]
     public string? Firstname { get; set; }
     [BsonElement("lastname")]
+    [JsonProperty("lastname")]
     public string? Lastname { get; set; }
     [BsonElement("phonenumber")]
+    [JsonProperty("phonenumber")]
     public string? PhoneNumber { get; set; }
     [BsonElement("date_created")]
+    [JsonProperty("date_created")]
     public DateTime DateCreated { get; set; }
     // [BsonRepresentation(BsonType.ObjectId)]
     [BsonElement("user_id")]
+    [JsonProperty("user_id")]
     public string? UserID  { get; set; }
 #endregion
 }