Add firefox.sh (see: tuna/issues#2016)

Signed-off-by: Harry Chen <i@harrychen.xyz>

firefox.sh

@@ -0,0 +1,21 @@
+#!/bin/bash
+set -e
+set -o pipefail
+
+_here=`dirname $(realpath $0)`
+apt_sync="${_here}/apt-sync.py" 
+yum_sync="${_here}/yum-sync.py"
+
+BASE_PATH="${TUNASYNC_WORKING_DIR}"
+BASE_URL="${TUNASYNC_UPSTREAM_URL:-"https://packages.mozilla.org/"}"
+export REPO_SIZE_FILE=/tmp/reposize.$RANDOM
+
+YUM_PATH="${BASE_PATH}/yum"
+APT_PATH="${BASE_PATH}/apt"
+
+# =================== APT repos ===============================
+# see: https://packages.mozilla.org/apt/dists/mozilla/InRelease
+"$apt_sync" --delete "${BASE_URL/}/apt" mozilla main amd64,i386,arm64 "${APT_PATH}"
+echo "APT finished"
+
+"${_here}/helpers/size-sum.sh" $REPO_SIZE_FILE --rm