Add support for service variables to Railway integration, add docs for Railway

frontend/src/hooks/api/integrationAuth/index.tsx

@@ -1,7 +1,7 @@
 export {
     useGetIntegrationAuthApps,
     useGetIntegrationAuthById,
+    useGetIntegrationAuthRailwayEnvironments,
+    useGetIntegrationAuthRailwayServices,
     useGetIntegrationAuthTeams,
-    useGetIntegrationAuthVercelBranches,
-    useGetRailwayEnvironments
-} from './queries';
+    useGetIntegrationAuthVercelBranches} from './queries';