Create an edge

Create an edge between an item "A" to an item "B".

No need to provide _from if fromKey is already provided. Same for _to and toKey.

fromKey and toKey are priority on _from and _to.

If type is not provided, an edge of type Child will be created.

Permissions: a on item "A".

          {
  "_from": "items/{{meKey}}",
  "fromKey": "{{meKey}}",
  "_to": "items/2345",
  "toKey": "2345",
  "type": "Child",
  "data": {}
}