[doc][skip ci] add docs.

Author: makasim

README.md

@@ -61,6 +61,10 @@ Features:
 [![Build Status](https://travis-ci.org/php-enqueue/fs.png?branch=master)](https://travis-ci.org/php-enqueue/fs)
 [![Total Downloads](https://poser.pugx.org/enqueue/fs/d/total.png)](https://packagist.org/packages/enqueue/fs)
 [![Latest Stable Version](https://poser.pugx.org/enqueue/fs/version.png)](https://packagist.org/packages/enqueue/fs)
+    * [Mongodb](docs/transport/mongodb.md)
+[![Build Status](https://travis-ci.org/php-enqueue/mongodb.png?branch=master)](https://travis-ci.org/php-enqueue/mongodb)
+[![Total Downloads](https://poser.pugx.org/enqueue/mongodb/d/total.png)](https://packagist.org/packages/enqueue/mongodb)
+[![Latest Stable Version](https://poser.pugx.org/enqueue/mongodb/version.png)](https://packagist.org/packages/enqueue/mongodb)
     * [Null](docs/transport/null.md).
 [![Build Status](https://travis-ci.org/php-enqueue/null.png?branch=master)](https://travis-ci.org/php-enqueue/null)
 [![Total Downloads](https://poser.pugx.org/enqueue/null/d/total.png)](https://packagist.org/packages/enqueue/null)

docs/transport/mongodb.md

@@ -0,0 +1,142 @@
+# Mongodb transport
+
+Allows to use [MongoDB](https://www.mongodb.com/) as a message queue broker. 
+
+* [Installation](#installation)
+* [Create context](#create-context)
+* [Send message to topic](#send-message-to-topic)
+* [Send message to queue](#send-message-to-queue)
+* [Send priority message](#send-priority-message)
+* [Send expiration message](#send-expiration-message)
+* [Send delayed message](#send-delayed-message)
+* [Consume message](#consume-message)
+
+## Installation
+
+```bash
+$ composer require enqueue/mongodb
+```
+
+## Create context
+
+```php
+<?php
+use Enqueue\Mongodb\MongodbConnectionFactory;
+
+// connects to localhost
+$connectionFactory = new MongodbConnectionFactory();
+
+// same as above
+$factory = new MongodbConnectionFactory('mongodb:');
+
+// same as above
+$factory = new MongodbConnectionFactory([]);
+
+$factory = new MongodbConnectionFactory([
+    'uri' => 'mongodb://localhost:27017/db_name',
+     'dbname' => 'enqueue',
+     'collection_name' => 'enqueue',
+     'polling_interval' => '1000',
+]);
+
+$psrContext = $factory->createContext();
+
+// if you have enqueue/enqueue library installed you can use a function from there to create the context
+$psrContext = \Enqueue\dsn_to_context('mongodb:');
+```
+
+## Send message to topic 
+
+```php
+<?php
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooTopic */
+
+$message = $psrContext->createMessage('Hello world!');
+
+$psrContext->createProducer()->send($fooTopic, $message);
+```
+
+## Send message to queue 
+
+```php
+<?php
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooQueue */
+
+$message = $psrContext->createMessage('Hello world!');
+
+$psrContext->createProducer()->send($fooQueue, $message);
+```
+
+## Send priority message
+
+```php
+<?php
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+
+$fooQueue = $psrContext->createQueue('foo');
+
+$message = $psrContext->createMessage('Hello world!');
+
+$psrContext->createProducer()
+    ->setPriority(5) // the higher priority the sooner a message gets to a consumer
+    //    
+    ->send($fooQueue, $message)
+;
+```
+
+## Send expiration message
+
+```php
+<?php
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooQueue */
+
+$message = $psrContext->createMessage('Hello world!');
+
+$psrContext->createProducer()
+    ->setTimeToLive(60000) // 60 sec
+    //    
+    ->send($fooQueue, $message)
+;
+```
+
+## Send delayed message
+
+```php
+<?php
+use Enqueue\AmqpTools\RabbitMqDlxDelayStrategy;
+
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooQueue */
+
+// make sure you run "composer require enqueue/amqp-tools".
+
+$message = $psrContext->createMessage('Hello world!');
+
+$psrContext->createProducer()
+    ->setDeliveryDelay(5000) // 5 sec
+    
+    ->send($fooQueue, $message)
+;
+````   
+
+## Consume message:
+
+```php
+<?php
+/** @var \Enqueue\Mongodb\MongodbContext $psrContext */
+/** @var \Enqueue\Mongodb\MongodbDestination $fooQueue */
+
+$consumer = $psrContext->createConsumer($fooQueue);
+
+$message = $consumer->receive();
+
+// process a message
+
+$consumer->acknowledge($message);
+// $consumer->reject($message);
+```
+
+[back to index](../index.md)