Complete the "HETIC challenge" section

[Aurelie-Mutschler]

Complete the file describing HETIC School challenge.

Indicative due date : June 23th, 2017

Criteria to close the issue :

• fork the repo
• edit the file challenges/hetic-school-challenge.md
• if you want to include images and so on, please put the additional files in challenges/picture/ folder
• make a pull request refering to this issue

[Aurelie-Mutschler]

ok so I think we give up for this ?

[Aurelie-Mutschler]

@clecoued what do you want to do with the contributions out of HETIC challenge ?
Do we integrate it somewhere in the gitbook ?

[clecoued]

I will create a dedicated page in the Gitbook in the "completed" Challenge section