❔ Question on how AddDbContext works

builder.Services.AddDbContext<Online_WriterContext>(options => options.UseSqlServer(builder.Configuration.GetConnectionString("Online_WriterContext") ?? throw new InvalidOperationException("Connection string 'Online_WriterContext' not found.")));

app.MapPost("/character", async( Character character, Online_WriterContext db) => {
    db.Character.Add(character);
    await db.SaveChangesAsync();
    return Results.Created($"/character/{character.Id}", character);
});