Add pre release instructions (#267)

RELEASING.md

@@ -1,18 +1,24 @@
-# Releasing a new version of Aragon Connect
+# Releasing an Aragon Connect version
 
-## Prepare the release notes
+This document describes the process to follow when releasing a [stable](#stable-releases) or [unstable](#unstable-releases) version of Connect.
+
+## Stable releases
+
+Stable releases are published under the `@latest` tag on npm, which is the default.
+
+### Prepare the release notes
 
 [Create a new draft release](https://github.com/aragon/connect/releases/new) and write the complete changelog for this version. Ideally this should be done before publishing on npm, so that there is no delay between the release on npm and the announcement.
 
-## Check that everything is ready
+### Check that everything is ready
 
 ```console
 yarn oao status
 ```
 
 Here you want to verify the current versions, and that private packages are marked as such so they don’t get published by mistake (especially for the examples).
 
-## Run the publication script
+### Run the publication script
 
 ```console
 yarn publish-version
@@ -27,7 +33,7 @@ This script will:
 - Generate a branch corresponding to the version tag.
 - Push `master`, the version branch and the version tag to GitHub.
 
-## Manual tasks on GitHub and GitBook
+### Manual tasks on GitHub and GitBook
 
 GitBook doesn’t support git tags, this is why a branch corresponding to the version tag gets created by the `publish-version` script. We now need to do two things: protect the branch on GitHub, and reorder the versions menu on GitBook.
 
@@ -45,10 +51,21 @@ Reorder the menu in GitBook:
 - Drag and drop the new version so that it is right below “latest”.
 - Click on the “Save” button, then “Merge”.
 
-## Publish the release on GitHub
+### Publish the release on GitHub
 
 Open the draft release, and assign the version tag to it (e.g. `v0.5.0`). Publish!
 
-## Announcement
+### Announcement
 
 Announce the release on our usual channels: Discord, Keybase, Twitter, etc.
+
+## Non-stable releases
+
+Unstable releases (release candidates, beta versions, or feature-specific releases) can be published using other npm tags than `@latest`. For beta or release candidates, use the `@next` tag. This process can be much more direct than the one we use for stable releases.
+
+It follows the steps described in the previous section with some notable differences:
+
+- Release notes they are optional in non-stable releases.
+- `yarn publish-version` should be prefixed with the `NPM_TAG` environment variable set to the tag you want to use, without the `@` (e.g. `NPM_TAG=next yarn publish-version`). Because you might want to use a non-incremental version number, you generally also have to specify the exact version using the `NEW_VERSION` environment variable (e.g. `NEW_VERSION=0.7.0-beta.2 NPM_TAG=next yarn publish-version`).
+- Publishing the release on GitHub is optional. If you do so, remember to check the “This is a pre-release” checkbox before doing so.
+- Announcing the version is optional too, and depends entirely on the context of the release.