{$push: {
        "progress.$.exercise":{
            "exercise":exercise
        }
}

{$push: {
        "progress.$.exercise.$.workout":{
            "_set":_set,
            "reps":reps,
            "weight":weight
        }
    }

var Workout = new mongoose.Schema({
    _set : {
        type: String
    },
    reps: {
        type: String
    },
    weight: {
        type: String
    }
});


var Exercise = new mongoose.Schema({
    exerciseName : {
        type: String
    },
    workout : [Workout]
});


var Progress = new mongoose.Schema({
    date : {
        type: String
    },
    name : {
        type: String
    },
    exercise : [Exercise]
});


var UserSchema = mongoose.Schema({
    username: {
        type: String,
        index:true
    },
    password: {
        type: String
    },
    email: {
        type: String
    },
    name: {
        type: String
    },
    progress : [Progress]

});


var User = module.exports = mongoose.model('User', UserSchema);