Startup.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using GDayMateBackend.Data;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.HttpsPolicy;
using Microsoft.AspNetCore.Mvc;
using Microsoft.EntityFrameworkCore;
using Microsoft.Extensions.Configuration;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.Extensions.Hosting;
using Microsoft.Extensions.Logging;
using Microsoft.OpenApi.Models;

namespace GDayMateBackend
{
    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.AddControllers();
            services.AddEntityFrameworkNpgsql();
            services.AddDbContext<AppDbContext>(o =>
            {
                o.UseNpgsql(Configuration.GetConnectionString("GDayMateDb"));
            });
            services.AddSwaggerGen(o =>
            {
                o.SwaggerDoc("v1", new OpenApiInfo
                {
                    Title = "GDayMate API Docs",
                    Version = "v1"
                });
            });
            services.AddCors(o =>
                o.AddPolicy("AllowAllPolicy", b =>
                {
                    b.AllowAnyOrigin().AllowAnyMethod().AllowAnyHeader();
                }));
        }

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

            if (env.IsDevelopment())
            {
                app.UseDeveloperExceptionPage();
            }

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

            app.UseHttpsRedirection();

            app.UseRouting();

            app.UseAuthorization();

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