Add project files.

Challenges/formAddChallenges.xaml.cs

@@ -0,0 +1,46 @@
+using System.Windows;
+using Npgsql;
+
+namespace SportsTrainingApp.Challenges
+{
+   
+    public partial class formAddChallenges : Window
+    {
+
+        public formAddChallenges()
+        {
+            InitializeComponent();
+            dtStart.SelectedDate = DateTime.Now;
+            dtEnd.SelectedDate = DateTime.Now.AddDays(1);
+        }
+
+        private void AddChallenges()
+        {
+            using (var conn = new NpgsqlConnection(formMain.connectionString))
+            {
+                conn.Open();
+                using (var cmd = new NpgsqlCommand($@"INSERT INTO dbo.challenges(
+	                                                    name, description, start_date, end_date)
+	                                                    VALUES (@name, @description, @start_date, @end_date);", conn))
+                {
+                    cmd.Parameters.AddWithValue("name", tbName.Text);
+                    cmd.Parameters.AddWithValue("description", tbDescription.Text);
+                    cmd.Parameters.AddWithValue("start_date", dtStart.SelectedDate);
+                    cmd.Parameters.AddWithValue("end_date", dtEnd.SelectedDate);
+                    cmd.ExecuteNonQuery();
+                }
+                this.Close();
+            }
+        }
+
+        private void Button_Click_1(object sender, RoutedEventArgs e)
+        {
+            AddChallenges();
+        }
+
+        private void Button_Click_2(object sender, RoutedEventArgs e)
+        {
+            this.Close();
+        }
+    }
+}