Get all from a Firestore collection in Flutter

I set up Firestore in my project. I created new collection named categories. In this collection I created three documents with uniq id. Now I want to get this collection in my Flutter application so I created CollectionReference:

Firestore.instance.collection('categories')

but I don't know what next.

I am using this plugin firebase_firestore: 0.0.1+1

Using StreamBuilder

import 'package:flutter/material.dart';
import 'package:firebase_firestore/firebase_firestore.dart';

class ExpenseList extends StatelessWidget {
  @override
  Widget build(BuildContext context) {
    return new StreamBuilder<QuerySnapshot>(
        stream: Firestore.instance.collection("expenses").snapshots,
        builder: (BuildContext context, AsyncSnapshot<QuerySnapshot> snapshot) {
          if (!snapshot.hasData) return new Text("There is no expense");
          return new ListView(children: getExpenseItems(snapshot));
        });
  }

  getExpenseItems(AsyncSnapshot<QuerySnapshot> snapshot) {
    return snapshot.data.documents
        .map((doc) => new ListTile(title: new Text(doc["name"]), subtitle: new Text(doc["amount"].toString())))
        .toList();
  }
}