Update config.json to new specification

[Roshanjossey]

This addresses issue #274
#274

[petertseng]

I have verified that in 8e1ceb5 that "exercises" is ordered in the same way as "problems".

[rbasso]

Thank you! 😄

[Roshanjossey]

@petertseng: I didn't understand why ordering of exercises is important in exercises key. As per the new changes, exercises will be fetched according to their order of difficulty right? As far as I understand ordering in exercises key is only relevant in the stage where difficulty of all exercises are 1

[petertseng]

As per the new changes, exercises will be fetched according to their order of difficulty right?

That was not my understanding of the plan as of exercism/discussions#60 (comment) and exercism/discussions#60 (comment) . It seems that the plan is to have exercises be fetched in the order they are listed in the file. Difficulty is not used in calculating when to fetch.

[Roshanjossey]

@petertseng: Thank you for clarifying that 👍