.NET Core Startup Configuration (including user specific settings)

Startup.cs

        public Startup(IHostingEnvironment env) {
            var builder = new ConfigurationBuilder()
             .SetBasePath(env.ContentRootPath)
             .AddJsonFile("appsettings.json", optional: true, reloadOnChange: true)
             .AddJsonFile($"appsettings.{env.EnvironmentName}.json", optional: true)
             .AddJsonFile($"appsettings.{Environment.UserName}.json", optional: true)
             .AddEnvironmentVariables();
            Configuration = builder.Build();
        }