Generate Email Automatically using Schedular

How can I customize the scheduler that will generate an email every day at 7 pm with the content of displaying all updated contact records? 

I have done some work and my custom scheduler is showing in the jobs dropdown but I am not getting any email.

custom/Extension/modules/Schedulers/Ext/ScheduledTasks/custom_job.php

And the second file is 

custom/Extension/modules/Scheduler/Ext/Language/en_us.custom_job.php

And it is showing in jobs dropdown

And even did a quick repair and rebuilt. Please let me know what I am doing wrong?