Startup.cs

using System.IO;
using CRUD.Models;
using CRUD.Models.DataManager;
using CRUD.Models.Repository;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;

namespace CRUD
{
    public class Startup
    {
        public Startup(IConfiguration configuration)
        {
            Configuration = configuration;
        }

        public IConfiguration Configuration { get; }

        // This method gets called by the runtime. Use this method to add services to the container.
        public void ConfigureServices(IServiceCollection services)
        {
            services.AddDbContext<RepositoryContext>(options => options.UseSqlServer(Configuration["ConnectionString:DB"]));
            services.AddScoped<IDataRepository<User>, UserManager>();
            services.AddControllers();
            services.AddSwaggerGen(c =>
            {
                //The generated Swagger JSON file will have these properties.
                c.SwaggerDoc("v1", new Microsoft.OpenApi.Models.OpenApiInfo { Title = "CRUD API", Version = "v1" });

                // Configure Swagger to use the xml documentation file
                var xmlFile = Path.ChangeExtension(typeof(Startup).Assembly.Location, ".xml");
                c.IncludeXmlComments(xmlFile);
            });
        }

        // This method gets called by the runtime. Use this method to configure the HTTP request pipeline.
        public void Configure(IApplicationBuilder app, IWebHostEnvironment env)
        {
            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

            app.UseRouting();

            app.UseAuthorization();

            app.UseEndpoints(endpoints =>
            {
                endpoints.MapControllers();
            });

            app.UseSwagger();
            app.UseSwaggerUI(c =>
            {
                c.SwaggerEndpoint("/swagger/v1/swagger.json", "CRUD API V1");
            });
        }
    }
}