Inline guide into rollup

.gitignore

@@ -3,4 +3,7 @@ node_modules
 .sapper
 .vscode
 /app/manifest
-/export
+/export
+
+# Needs to be taken from the main rollup repo
+guide/en

.gitmodules

@@ -0,0 +1,3 @@
+[submodule "rollup-submodule"]
+	path = rollup-submodule
+	url = https://github.com/rollup/rollup.git

README.md

@@ -1,22 +1,36 @@
 # Rollupjs.org
 
-This is the source code for the website!
+This is the source code for the website. Note that the actual guide is now part of the [main rollup repo](https://github.com/rollup/rollup/tree/master/guide) and needs to be updated there, see below.
 
 ## Steps to build the website locally
 
 1. `npm install`
-2. `npm run dev`
-3. Open up http://localhost:3000
-
-
-## Adding translations
-
-Translations into other languages are warmly welcomed. Make a copy of the `guide/en` directory, renaming it to your language (e.g. `guide/fr`), and update the markdown files inside. Once done, the translation will be available at `/[lang]`.
+2. `npm run update-guide`
+3. `npm run dev`
+4. Open up http://localhost:3000
+
+## Updating the guide contents
+
+The guide is part of the main rollup repo, which again is added to this repo in form of a submodule. Running `npm run update-guide` should automatically initialize the submodule and copy the latest guide into a local folder. To update the guide contents:
+
+1. Update the guide in a fork or a branch (if you have access rights) of the main rollup repo and make a pull request. Pull requests that add or modify features should always update the guide as well.
+2. Once it is merged, check out the latest master branch in the submodule:
+   ```bash
+   cd rollup-submodule
+   git checkout master
+   git pull
+   ```
+3. Commit the new branch in the main repo:
+   ```bash
+   cd ..
+   git add rollup-submodule
+   git commit -m "Update guide"
+   ```
+
+Steps 2 and 3 should be done by the person merging the pull request in the main rollup repo. Once the commit has been pushed to `origin/master`, the website should be updated by the CI automatically. If necessary instead of checking out latest master, it is also possible to check out any other commit to e.g. test a pull request.
 
 ## Style Guidelines
 
-_(Note: This section will be updated on an as-needed basis)_
-
 - Please use `-` for bulleted list items.
 - Please set a preferred line length of 100 characters in your editor for Markdown files in this repository.
-- Please do not use hard line breaks to format blocks of plain text. Rather, please enable soft-line breaks in your editor.
+- Please do not use hard line breaks to format blocks of plain text. Rather, please enable soft-line breaks in your editor.