Major update

divisions/Handlers/GetDivisionByIdQueryHandler.cs

@@ -0,0 +1,25 @@
+using System;
+using Divisions.DbContexts;
+using Divisions.Entities;
+using Divisions.Queries;
+using MediatR;
+using Microsoft.EntityFrameworkCore;
+
+namespace Divisions.Handlers
+{
+	public class GetDivisionByIdQueryHandler : IRequestHandler<GetDivisionByIdQuery, Division>
+	{
+		private readonly DivisionsContext _dbContext;
+
+		public GetDivisionByIdQueryHandler(DivisionsContext dbContext)
+		{
+			_dbContext = dbContext ?? throw new ArgumentNullException(nameof(dbContext));
+		}
+
+		public async Task<Division> Handle(GetDivisionByIdQuery request, CancellationToken cancellation)
+		{
+			return await _dbContext.Divisions.Where(d => d.Id == request.DivisionId).FirstOrDefaultAsync();
+		}
+	}
+}
+