npm install --save koa-rethinkdb

var rethinkdbPool = require('koa-rethinkdb');

var options = {
    host:'localhost',
    port:28015,
    db:'marvel',
    authKey:'hunter2'
};

app.use(rethinkdbPool(options, maxConcurrentConnection || 10, minConcurrentConnection || 2, idleTimeoutMillis || 30000));

var rethinkdbPool = require('koa-rethinkdb');
var r             = require('rethinkdb');
var chan          = require('chan');

app.use(rethinkdbPool(options));
app.use(function *(next) {

    // get the list of table
    var ch1 = chan();
    var query1 = r.db('test').tableList().run(this.rethinkdb, ch1);

    var list = yield ch1;

    // select a few documents
    ch2 = chan();
    r.db('test').table('foobar').limit(10).run(this.rethinkdb, ch2);
    cursor = yield ch2;

    result = yield cursor.toArray;

    yield next;
    // connections are released back to the pool.
});