services/horizon: Sort offers by amount when the price is the same in /order_book

[bartekn]

What problem does your feature solve?

Would be great if price levels were sorted by amount or offer ID if the price is the same in /order_book. This will help tools like horizon-cmp (less false positives).

What would you like to see?

One Horizon returned:

    {
      "price_r": {
        "n": 45,
        "d": 10000000
      },
      "price": "0.0000045",
      "amount": "0.0017955"
    },
    {
      "price_r": {
        "n": 9,
        "d": 2000000
      },
      "price": "0.0000045",
      "amount": "0.0700000"
    },

The other one:

    {
      "price_r": {
        "n": 9,
        "d": 2000000
      },
      "price": "0.0000045",
      "amount": "0.0700000"
    },
    {
      "price_r": {
        "n": 45,
        "d": 10000000
      },
      "price": "0.0000045",
      "amount": "0.0017955"
    },

Would be great if order was the same on both servers.

What alternatives are there?

Technically horizon-cmp could sort it before comparing but looks like it's easier to fix in Horizon.

[bartekn]

Actually, shouldn't the two price levels be merged into one? Numerator and denominator are different but n/d value is exactly the same.