Update name of parents field to match API and add child_count
Update name of parents field to match API and add child_count

pattisdr/ember-preprints,hmoco/ember-preprints,laurenrevere/ember-preprints,baylee-d/ember-preprints,baylee-d/ember-preprints,hmoco/ember-preprints,CenterForOpenScience/ember-preprints,pattisdr/ember-preprints,caneruguz/ember-preprints,caneruguz/ember-preprints,CenterForOpenScience/ember-preprints,laurenrevere/ember-preprints