Consider the following models:
User:
  id: ObjectID
Group:
  id: ObjectID
  users: []
If I had a group collection like:
Group = [{
    id: 1,
    users: [1,2,3,4,5]
  },
  {
    id: 2,
    users: [1,6,7]
  }
]
How could I get all the Groups that container the User ID 1 in the groups.users array?
