rubygems.org hosts its resource in Amazon S3 which is disturbed by GFW. So gem and bundle complain from time to time.

This guide assumes you used docker installation. This guide also has a version in Chinese. 中文指南

Add a template

Open your congiruation file, say, app.yml.

Add a reference to the china template:

templates:
  - "templates/postgres.template.yml"
  - "templates/redis.template.yml"
  - "templates/sshd.template.yml"
  - "templates/web.template.yml"
  - "templates/web.china.yml"

Bootstrap docker container

Rebuild your app

./launcher rebuild app

Or bootstrap:

./launcher bootstrap app

You are done! Everything should work then.

Source: https://meta.discourse.org/t/replace-rubygems-org-with-taobao-mirror-to-resolve-network-error-in-china/21988