feature #6: implement PostgresJson

add Article, Citien and User Entities
implement Article.findById()

resources/application.conf

@@ -7,3 +7,15 @@ ktor {
         modules = [ fr.dcproject.ApplicationKt.module ]
     }
 }
+
+app {
+    envName = prod
+}
+
+db {
+    host = localhost
+    database = dc-project
+    username = dc-project
+    password = dc-project
+    port = 5432
+}