public void Configure(IApplicationBuilder app, IWebHostEnvironment env) 

                              {
                                  
 var builder = new ConfigurationBuilder() 
.SetBasePath(env.ContentRootPath) 
.AddJsonFile("appsettings.json", optional: true, reloadOnChange: true) 
.AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true); 
            if (env.IsDevelopment())

                                  {
                                      
            {
                                          
 app.UseDeveloperExceptionPage(); 

                                      }
                                  }
                                  
 else
            {
                                      
 app.UseExceptionHandler("/Home/Error"); 

                                  } 
 app.UseStaticFiles(); 

 app.UseRouting(); 

 app.UseAuthorization(); 
 PrepDB.PrepPoupulation(app); 

 app.UseEndpoints(endpoints => 
            {
                
 endpoints.MapControllerRoute(
 name: "default", 
 pattern: "{controller=Customers}/{action=Index}/{id?}"); 

            }); 

                              }