Mongodb-odm composer request - php

Question

I have a problem with requesting my composer for mongodb-odm by command: composer request doctrine/mongodb-odm. Every time I run this command I get an error message saying:
Your requirements could not be resolved to an installable set of packages.
Problem 1
- doctrine/mongodb-odm 1.0.0 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.1 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.2 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.3 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb-odm 1.0.4 requires doctrine/mongodb ~1.2 -> satisfiable by doctrine/mongodb[1.2.0, 1.2.1].
- doctrine/mongodb 1.2.1 requires ext-mongo ^1.2.12 -> the requested PHP extension mongo is missing from your system.
- doctrine/mongodb 1.2.0 requires ext-mongo ^1.2.12 -> the requested PHP extension mongo is missing from your system.
- Installation request for doctrine/mongodb-odm ^1.0 -> satisfiable by doctrine/mongodb-odm[1.0.0, 1.0.1, 1.0.2, 1.0.3, 1.0.4].
To enable extensions, verify that they are enabled in those .ini files:
- /etc/php.ini
You can also run `php --ini` inside terminal to see which files are used by PHP in CLI mode.
Installation failed, reverting ./composer.json to its original content.
Now, my problem is that I get this error even though my configuration seems to be fine. I did some research so I know what should be included in php.ini file. So, my php.ini file contains line:
extension="mongo.so"
There are two php.ini files in my Mac, therefore, just for insurance, I put this line even into the other one. No change.
I am using MacBook Pro (13-inch, Mid 2012) - OS X 10.11.3
Any help will be appreciated.