Translators need to set up their environment

Fixes #1263

docs/translations.md

@@ -9,6 +9,7 @@ Before you start working on a translation, look through the [open pull requests]
 If there's not, then today is your day to lead this effort! Here's how to start:
 
 1. [Fork this repository](https://github.com/github/opensource.guide/fork)
+1. [Set up your environment](../CONTRIBUTING.md#setting-up-your-environment)
 1. Create a new branch for your translation work e.g. `es`.
 1. Copy `_data/locales/en.yml` to your target language file e.g. `_data/locales/es.yml` and translate all the strings.
 1. Create a new directory in `_articles/` for your language e.g. `_articles/es/`, copy each guide from `_articles/` into that folder and translate the content in each guide, except for the field names in the front matter between the `---`s at the top of each file, e.g., `title:` should remain unchanged. Remove the `toc:` fields (they are only used for English).