Create a Router class that implements RouterInterface.

All files must follow PSR-0, PSR-1 and PSR-2 (tabs can be used instead of spaces). Keep the project simple and try not to over-engineer things!

Write PHPUnit tests inside tests/ (you must create the folder).

Commit every step you make, even if it has errors. Please don't commit all the functionality and tests at once, let us see in which order did you write your code.

In case you find it necessary to write documentation, feel free to create a Markdown document or comment the code. This step is not required.