add exercice stub

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
add README file

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
add Student impl

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>
cleaned README file

Signed-off-by: Alexandre Terrasa <alexandre@moz-code.org>