start api to display dossier

missing pj, fields, exercices

app/serializers/etablissement_serializer.rb

@@ -0,0 +1,14 @@
+class EtablissementSerializer < ActiveModel::Serializer
+  attributes :siret,
+             :siege_social,
+             :naf,
+             :libelle_naf,
+             :adresse,
+             :numero_voie,
+             :type_voie,
+             :nom_voie,
+             :complement_adresse,
+             :code_postal,
+             :localite,
+             :code_insee_localite
+end