Add shell check to pre-cmmit hooks & fix issues reported by it (#2579)

run_alembic_check.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 # first apply migrations
-export PATH=$PATH:.venv/bin
+export PATH="${PATH}:.venv/bin"
 alembic upgrade head
 # then check if the database is up to date with the models
 alembic check