Paper assignment edges not correctly saved

[melisabok]

Use the values that are represented in the invitation.reply.

{
"_id": "5d029a80854c2f21e01ef8f3",
"id": "r1mgdYczlkH",
"invitation": "auai.org/UAI/2019/Conference/-/Aggregated_Score",
"label": "aggregateScore",
"weight": 0,
"head": "H1GBIvze1H",
"tail": "r3@fb.com",
"signatures": [
"r3@fb.com"
],
"readers": [
"everyone"
],
"writers": [
"auai.org/UAI/2019/Conference/-/Assignment_Configuration"
],
"nonreaders": [],
"cdate": 1560451712489,
"ddate": null,
"tcdate": 1560451712489,
"tmdate": 1560451712489,
"tddate": null,
"tauthor": null
},

[marshall62]

done