how to find and push data into array in mongoose

I have used this schema:-

var candidateSchema = new mongoose.Schema({
    name : String,
    partyName: {type: String, unique: true},
    information: String
});
var candidate = mongoose.model("candidate", candidateSchema);

var adminSchema = new mongoose.Schema({
    electionName : {type: String, unique: true},
    endDate      : {type: Date},
    candidates   : [{type: mongoose.Schema.Types.ObjectId, 
                    ref: "candidate"}]  
});
 var addElection = mongoose.model("addElection", adminSchema);

How can i push the candidateSchema's data into candidate[] array.

via Abhijeet Baviskar