Filter Posting List by ID

[calummoore]

As per the discuss thread (Filter Posting List by ID), it would be really useful to be able to filter a Posting List by ID.

E.g. in the friends node below.

me (id: <uid>) {
    name
    friends (id: <uid>) {
        name
    }
}

As suggested by @manishrjain, it might be a good idea to use a fn to wrap the <uid> and to use filter instead of (id: <uid>).

[pawanrawal]

This has been merged to master.