Update livre.play.deux/04-firstapp.next.md

Fix an error in the explanation of the @OneToMany annotation 
Merge pull request #40 from kbenhdech/patch-1

Update livre.play.deux/04-firstapp.next.md
gen book
remerciements
Update livre.play.deux/04-firstapp.next.md

Correction typographique sur l'attribut action des formulaires.
Merge pull request #41 from dblugeon/patch-1

Update livre.play.deux/04-firstapp.next.md
@BrunoVernay