gistfile1.txt

> db.followings.find()

{ "_id" : ObjectId("4c2be9944fcb0625aa00002d"), "followed_id" : ObjectId("4c2be9944fcb0625aa00002c"), "follower_id" : ObjectId("4c2be9944fcb0625aa00002b"), "active" : true }
{ "_id" : ObjectId("4c2be9954fcb0625aa000030"), "followed_id" : ObjectId("4c2be9954fcb0625aa00002f"), "follower_id" : ObjectId("4c2be9954fcb0625aa00002e"), "active" : true }

map = function( ) {
  emit( followed.permalink, followed );
};

reduce = function( k, vals ) { return 1; }

res = db.followings.mapReduce( m, r, { query : { permalink : 'ngw' } } );