Merge fix_resolver_dev dans master

See merge request br/sigma-backend!17

last type is PrivatePost

This was terrible

This reverts commit 0c6ce39a.

Remplacement de express-graphql par Apollo Server

See merge request br/sigma-backend!15

utilise le webpack-graphql-loader

Utilisation de Typescript

Closes #3

See merge request br/sigma-backend!12

Capacité de remplacer des valeurs dynamiquement par des envars

resolves #8