Add depends_on for nginx so it waits until the limesurvey app is ready (#102)

By adding a depends_on in lime-web, it will wait for the limesurvey app to be ready to accept connections.

docker-compose.fpm.alpine.yml

@@ -20,6 +20,8 @@ services:
     image: nginx:alpine
     links:
       - limesurvey
+    depends_on:
+      - limesurvey
     ports:
       - "8080:80"
     volumes: