controller.js

var data = {
    "name": "Affinity",
    "mainDeck": [
        {"qty": 4, "name": "Mox Opal"},
        {"qty": 4, "name": "Cranial Plating"},
        {"qty": 3, "name": "Glimmervoid"},
        {"qty": 4, "name": "Darksteel Citadel"},
        {"qty": 4, "name": "Galvanic Blast"},
        {"qty": 3, "name": "Etched Champion"},
        {"qty": 4, "name": "Ornithopter"},
        {"qty": 2, "name": "Memnite"},
        {"qty": 4, "name": "Sigil Pest"},
        {"qty": 4, "name": "Springleaf Drum"},
        {"qty": 1, "name": "Island"},
        {"qty": 3, "name": "Steel Overseer"},
        {"qty": 4, "name": "Thoughtcast"},
        {"qty": 4, "name": "Arcbound Ravager"},
        {"qty": 4, "name": "Blinkmoth Nexus"},
        {"qty": 4, "name": "Inkmoth Nexus"},
        {"qty": 4, "name": "Vault Skirge"}
    ]
}

$http.post('http://localhost:8080/api/decks', data);

deck.js

var mongoose     = require('mongoose');
var Schema       = mongoose.Schema;

var DeckSchema   = new Schema({
    name: String,
    mainDeck: [
        {
            qty: Number,
            name: String
        }
    ]
});

module.exports = mongoose.model('Deck', DeckSchema);