feat: initial datamodel + ef connection and migrations

Initial version of the data model
Includes EF initialization and migrations
EF migrations are applied on application start

TournamentOrganizer/Models/Participant.cs

@@ -0,0 +1,29 @@
+using System;
+using System.Collections.Generic;
+using System.ComponentModel.DataAnnotations;
+using System.ComponentModel.DataAnnotations.Schema;
+using Microsoft.EntityFrameworkCore;
+
+namespace TournamentOrganizer.Models;
+
+[PrimaryKey(nameof(RoundId), nameof(PlayerId))]
+public class PlayerParticipant
+{
+    public int RoundId { get; set; }
+    public int PlayerId { get; set; }
+
+    public required Player Player { get; set; }
+    public required Round Round { get; set; }
+}
+
+
+public class TeamParticipant
+{
+    public int MatchId { get; set; }
+    public int TeamId { get; set; }
+    public int Seed { get; set; }
+    public int Score { get; set; }
+
+    public required Team Team { get; set; }
+    public required Match Round { get; set; }
+}