Extensions needed for dashboard metrics

[dotnetshadow]

Hi there,

I noticed with the latest release 1.6.7.7, you have an extension method to use .UseRedisStore() which is nice.

The problem I'm facing now is that if I use this extension method then I'm not sure how I can read dashboardmetrics without passing in a storage and redefining the storage:

services.AddHangfire(configuration =>
{
                configuration.UseRedisStorage("127.0.0.1:6379,allowAdmin=true,abortConnect=false", new RedisStorageOptions { Db = 1, Prefix = "hangfire:app1:", SucceededListSize = 10, DeletedListSize = 10 });
                configuration.UseColouredConsoleLogProvider();
});

// NEED TO GET STORAGE HERE----------------------------V
GlobalConfiguration.Configuration.UseDashboardMetric(storage.GetDashboardMetricFromRedisInfo("Redis Version", RedisInfoKeys.redis_version));

I've actually seen another library implement this by allowing the RedisStrorage to have an extension method. You can see details of this here
https://github.com/BoltR/Hangfire.Redis.StackExchange

[marcoCasamento]

Yep, that has been added by @codeyu, a fluent syntax for configuration really helps on readability.
Seems like a nice addition, would you mind a PR ?

[pieceofsummer]

I think GetDashboardMetricFromRedisInfo() should not be an instance method of RedisStorage at all. It can safely be made static, or even turn into an extension method on IGlobalConfiguration.