Gradebook

Hi

I have an application whereby I can have students perfrom certain tasks on my Company's software platform remotely, and then we run ruby scripts to check if the tasks are completed correctly.  The scripts return a simple pass/fail.

I need to integrate this system into my Moodle platform, by adding it as an activity to a course,  in such a way as they need to get a 'pass' in order to access the next activity in the course.  The Moodle Activity itself could be just a pointer to our existing task instructions, and I can easily have my Ruby script update the relevant database table, but I dont know what one, or how to set up the activity.  

Any ideas on type of activity should I use, and how can I programatically update the database, whic table etc? I was advised in another forum that I could use an 'integration activity module', but I'm not sure what that means or how to implement it.

Any pointers would be great.