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/Database/TournamentContext.cs

@@ -0,0 +1,40 @@
+using System;
+using System.IO;
+using Microsoft.Data.Sqlite;
+using Microsoft.EntityFrameworkCore;
+using TournamentOrganizer.Models;
+
+namespace TournamentOrganizer;
+
+public class TournamentContext : DbContext
+{
+    public DbSet<Event> Events { get; set; }
+    public DbSet<Game> Games { get; set; }
+    public DbSet<Match> Matches { get; set; }
+    public DbSet<TeamParticipant> TeamParticipants { get; set; }
+    public DbSet<PlayerParticipant> PlayerParticipants { get; set; }
+    public DbSet<Player> Players { get; set; }
+    public DbSet<Round> Rounds { get; set; }
+    public DbSet<Team> Teams { get; set; }
+    public DbSet<Tournament> Tournaments { get; set; }
+
+    protected override void OnConfiguring(DbContextOptionsBuilder optionsBuilder)
+    {
+        string datadir = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.ApplicationData), "TournamentOrganizer");
+        Directory.CreateDirectory(datadir);
+        string dbfile = Path.Combine(datadir, "sqlite.db");
+        optionsBuilder.UseSqlite(new SqliteConnectionStringBuilder()
+        {
+            DataSource = dbfile,
+            Mode = SqliteOpenMode.ReadWriteCreate,
+            ForeignKeys = true,
+            RecursiveTriggers = true
+        }.ToString());
+    }
+
+    protected override void OnModelCreating(ModelBuilder modelBuilder)
+    {
+        base.OnModelCreating(modelBuilder);
+    }
+
+}