docs: how to use Alerts

[Meng-Heng]

follows: #41

This PR is ready for review.

[darcywong00]

shared-sites/bootstrap.inc.sh

Lines 95 to 132 in ad297a4

	function _bootstrap_configure_common() {
	local BOOTSTRAP_COMMON="$BOOTSTRAP_ROOT/_common"
	local ASSET_LOGOS="assets/sil-logos-2024"
	local COMMON_FILES=(
	builder.inc.sh
	docker.inc.sh
	keyman-local-ports.inc.sh
	JsonApiFailure.php
	KeymanHosts.php
	KeymanSentry.php
	MarkdownHost.php
	ImageRandomizer.php
	)
	local IMG_FILES=(
	sil-logo-abbysinica.png
	sil-logo-andika-v1.png
	sil-logo-andika-v2.png
	sil-logo-annapurna.png
	sil-logo-tai-heritage-pro.png
	)
	local common_file=
	local img_file=
	_bootstrap_echo "Downloading _common files"
	rm -rf "$BOOTSTRAP_COMMON"
	mkdir -p "$BOOTSTRAP_COMMON"
	for common_file in "${COMMON_FILES[@]}"; do
	_bootstrap_download "_common/$common_file" "$BOOTSTRAP_COMMON/$common_file"
	done
	for img_file in "${IMG_FILES[@]}"; do
	mkdir -p "$BOOTSTRAP_COMMON/$ASSET_LOGOS/"
	_bootstrap_download "_common/$ASSET_LOGOS/$img_file" "$BOOTSTRAP_COMMON/$ASSET_LOGOS/$img_file"
	done
	_bootstrap_echo "All _common files downloaded"
	}

We may need to update to also download the new .png file.
Since the website will pull down this README, the link-checkers would fail if the assets img doesn't exist.

[Meng-Heng]

@darcywong00, I rebased this to alerts/v0.12. Can this be merge for testing?

[darcywong00]

lgtm

[mcdurdin]

We don't want 500 errors from Markdown. This needs to be fixed -- Markdown should never cause the server to crash.