Need API routes for Trade Routes Feature

[patrickrb]

This should be an epic. I need to wrap my head around how to do trade routes with the data we have.

[patrickrb]

So far I have an aggregation query for mongo that returns the mins and maxes for a selected commodity:

db.listings.aggregate(

  // Pipeline
  [
    // Stage 1
    {
      $match: {
       commodity_id: NumberInt(35)
      }
    },

    // Stage 2
    {
      $project: {
        "station_id": 1,
        "sell_price": 1,
        "buy_price": 1,
        "commodity_id": 1
      }
    },

    // Stage 3
    {
      $group: {
            _id: { station_id: "$station_id",commodity_id: "$commodity_id"},
        buy_max:{ $max: "$buy_price"},
        sell_min: { $min: "$sell_price"}
      }
    }

  ]

  // Created with 3T MongoChef, the GUI for MongoDB - http://3t.io/mongochef

);