public static IConfigurationRoot Configuration;

    public Startup(IApplicationEnviroment appEnv)
    {
        var builder = new ConfigurationBuilder()
            .SetBasePath(appEnv.ApplicationBasePath)
            .AddJsonFile("config.json")
            .AddEnvironmentVariables();

        Configuration = builder.Build();
    }

using Microsoft.Framework.Configuration;

using Microsoft.Extensions.Configuration;

IApplicationEnviroment appEnv