Merge pull request #240 from rmacklin/checkout-stable-branch

Avoid unnecessary detached HEAD state in `boot.sh` and check out `stable` branch in `migrate.sh`

bin/omakub-sub/migrate.sh

@@ -1,5 +1,6 @@
 cd $OMAKUB_PATH
 last_updated_at=$(git log -1 --format=%cd --date=unix)
+git checkout stable
 git pull
 
 for file in $OMAKUB_PATH/migrations/*.sh; do

boot.sh

@@ -20,7 +20,7 @@ rm -rf ~/.local/share/omakub
 git clone https://github.com/basecamp/omakub.git ~/.local/share/omakub >/dev/null
 if [[ $OMAKUB_REF != "master" ]]; then
 	cd ~/.local/share/omakub
-	git fetch origin "${OMAKUB_REF:-stable}" && git checkout FETCH_HEAD
+	git fetch origin "${OMAKUB_REF:-stable}" && git checkout "${OMAKUB_REF:-stable}"
 	cd -
 fi