Major update

seasons/Handlers/GetSeasonByIdQueryHandler.cs

@@ -0,0 +1,25 @@
+using System;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+using Seasons.DbContexts;
+using Seasons.Entities;
+using Seasons.Queries;
+
+namespace Seasons.Handlers
+{
+	public class GetSeasonByIdQueryHandler : IRequestHandler<GetSeasonByIdQuery, Season>
+	{
+		private readonly SeasonsContext _dbContext;
+
+		public GetSeasonByIdQueryHandler(SeasonsContext dbContext)
+		{
+			_dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
+		}
+
+		public async Task<Season> Handle(GetSeasonByIdQuery request, CancellationToken cancellationToken)
+		{
+			return await _dbContext.Seasons.Where(s => s.Id == request.SeasonId).FirstOrDefaultAsync();
+		}
+	}
+}
+