Issue with JSON API for the jobs

[exoticDFT]

It seems that in the code that generates our JSON API for the jobs can end up without a "," for the last job in the feed, or has an extra "," if the last job in our for loop is expired. One way to fix this seems to be always adding the "," for each job in the for loop. It partially seems like this was the expectation as the last element in our generated JSON is an empty object, i.e. "{}".