[feature] ability to immediately start an @every job

[wsw70]

Would it be possible to add an option to start jobs scheduled as @every immediately (and not after the interval)?

The docs mention that

For example, "@every 1h30m10s" would indicate a schedule that activates after 1 hour, 30 minutes, 10 seconds, and then every interval after that.

I believe that there it would be interesting to have the immediate start - for instance, I need to do

googleCalendar()
forecast()
temperature()
c := cron.New()
c.AddFunc("@every 1min", googleCalendar)
c.AddFunc("@every 15min", forecast)
c.AddFunc("@every 12min", temperature)
c.Start()

instead of, say

c := cron.New({intervalRunAtStartup: true})
c.AddFunc("@every 1min", googleCalendar)
c.AddFunc("@every 15min", forecast)
c.AddFunc("@every 12min", temperature)
c.Start()

(see also #396)

[ivanjaros]

you can do this by simply calling Run() on every job when you are calling Start() on cron. since you have to provide the jobs to the cron, you already have access to them so calling Run() is not a problem.

[zeewell]

#436