Updated model and Repository class

Models/User.cs

@@ -9,8 +9,8 @@ namespace TextSender_API.Models;
 public class User
 {
 #region Properties
-    [BsonElement("_id")]
-    public ObjectId UserID { get; set; }
+    // [BsonElement("_id")]
+    public ObjectId Id { get; set; }
     [BsonElement("firstname")]
     public string? Firstname { get; set; }
     [BsonElement("lastname")]

Repositories/UserRepository.cs

@@ -3,15 +3,40 @@ using System;
 using MongoDB.Bson;
 using MongoDB.Driver;
 
+using TextSender_API.Models;
+
 namespace TextSender_API.Repositories;
 
 
 public class UserRepository
 {
-    #region Properties
+    #region Fields
+    private string _connectionString;
+    private string _databaseName;
+    private string _tableName;
     #endregion
 
 
     #region Constructors
+    public UserRepository(string connectionString)
+    {
+        this._connectionString = connectionString;
+        this._databaseName = "TextSender";
+        this._tableName = "Users";
+    }
+    #endregion
+
+    #region Metods
+    public void CreateUser(User user)
+    {
+        var client = this.InitializeClient();
+
+        var coll = client.GetDatabase(this._databaseName).GetCollection<User>(this._tableName);
+        coll.InsertOne(user);
+    }
+    private MongoClient InitializeClient()
+    {
+        return new MongoClient(this._connectionString);
+    }
     #endregion
 }