Add doc for script installFromGitHub.sh

docs/installing_from_ci.md

@@ -0,0 +1,51 @@
+## Installing from CI
+
+<!--- TOC -->
+
+  * [Installing from Buildkite](#installing-from-buildkite)
+  * [Installing from GitHub](#installing-from-github)
+    * [Create a GitHub token](#create-a-github-token)
+  * [Provide artifact URL](#provide-artifact-url)
+  * [Next steps](#next-steps)
+
+<!--- END -->
+
+Installing APK build by the CI is possible
+
+### Installing from Buildkite
+
+The script `./tools/install/installFromBuildkite.sh` can be used, but Builkite will be removed soon. See next section.
+
+### Installing from GitHub
+
+To install an APK built by a GitHub action, run the script `./tools/install/installFromGitHub.sh`. You will need to pass a GitHub token to do so.
+
+#### Create a GitHub token
+
+You can create a GitHub token going to your Github account, at this page: [https://github.com/settings/tokens](https://github.com/settings/tokens).
+
+You need to create a token (classic) with the scope `repo/public_repo`. So just check the corresponding checkbox.
+Validity can be long since the scope of this token is limited. You will still be able to delete the token and generate a new one.
+Click on Generate token and save the token locally.
+
+### Provide artifact URL
+
+The script will ask for an artifact URL. You can get this artifact URL by following these steps:
+
+- open the pull request
+- in the check at the bottom, click on `APK Build / Build debug APKs`
+- click on `Summary`
+- scroll to the bottom of the page
+- copy the link `vector-Fdroid-debug` if you want the F-Droid variant or `vector-Gplay-debug` if you want the Gplay variant.
+
+The copied link can be provided to the script.
+
+### Next steps
+
+The script will download the artifact, unzip it and install the correct version (regarding arch) on your device.
+
+Files will be added to the folder `./tmp/DebugApks`. Feel free to cleanup this folder from time to time, the script will not delete files.
+
+### Future improvement
+
+The script could ask the user for a Pull Request number and Gplay/Fdroid choice like it was done with Buildkite script. Using GitHub API may be possible to do that.

tools/install/installFromGitHub.sh

@@ -4,7 +4,8 @@
 set -e
 
 if [[ "$#" -ne 1 ]]; then
-  echo "Usage: $0 GitHub_token" >&2
+  echo "Usage: $0 GitHub_Token" >&2
+  echo "Read more about this script in the doc ./docs/installing_from_ci.md"
   exit 1
 fi