Add double quotes to avoid synatx errors

roles/matrix-postgres/templates/sql/init-additional-db-user-and-role.sql.j2

@@ -2,18 +2,18 @@
 -- Seen here: https://stackoverflow.com/a/49858797
 DO $$
 BEGIN
-  CREATE USER {{ additional_db.username }};
+  CREATE USER "{{ additional_db.username }}";
   EXCEPTION WHEN DUPLICATE_OBJECT THEN
-  RAISE NOTICE 'not creating user {{ additional_db.username }}, since it already exists';
+  RAISE NOTICE 'not creating user "{{ additional_db.username }}", since it already exists';
 END
 $$;
 
 -- This is useful for initial user creation (since we don't assign a password above) and for handling subsequent password changes
 -- TODO - we should escape quotes in the password.
-ALTER ROLE {{ additional_db.username }} PASSWORD '{{ additional_db.password }}';
+ALTER ROLE "{{ additional_db.username }}" PASSWORD '{{ additional_db.password }}';
 
 -- This will generate an error on subsequent execution
-CREATE DATABASE {{ additional_db.name }} WITH LC_CTYPE 'C' LC_COLLATE 'C' OWNER {{ additional_db.username }};
+CREATE DATABASE "{{ additional_db.name }}" WITH LC_CTYPE 'C' LC_COLLATE 'C' OWNER "{{ additional_db.username }}";
 
 -- This is useful for changing the database owner subsequently
-ALTER DATABASE {{ additional_db.name }} OWNER TO {{ additional_db.username }};
+ALTER DATABASE "{{ additional_db.name }}" OWNER TO "{{ additional_db.username }}";