Add global reverse proxy timeout settings (fixes #74)

src/nginxconfig/templates/global_sections/index.js

@@ -28,6 +28,7 @@ export { default as HTTPS } from './https';
 export { default as Security } from './security';
 export { default as PHP } from './php';
 export { default as Python } from './python';
+export { default as ReverseProxy } from './reverse_proxy';
 export { default as Performance } from './performance';
 export { default as Logging } from './logging';
 export { default as NGINX } from './nginx';