Add sql script

we changed the db update process to use alembic, but we need to keep the
sql migration scripts for the user using an old versioned old.

The user having an old database thus has to do:

source/script/update_db.sh settings.sh

--> to update one last time the db schema to the alembic known schema

PYTHONPATH=. alembic stamp 35c20e6103d6

--> to tell alembic that the db is in the same version as the file
35c20e6103d6_create_tables.py

PYTHONPATH=. alembic upgrade head

--> to update the schema

NOTE: this has to be done only once, afterward only the alembic upgrade head is required