Install update

correction of the install script

migration to alembic

fix alembic bug regarding schema handling
The removed method in this commit did not work. IIRC, it was about the return code sent by psql. This one does not send the return code we need so i preferred to encapsulate the command output (empty or not) in a variable "encap" that i check just after.

About the "-", it's not mandatory but i prefer login shells (no psql/shell history issue about permissions, …). For escaping, it's not bound to "-". i could use simple quote for psql command but we need variables.