Add note on README.rst about now hstore extension is not installed automatically
Add note on README.rst about now hstore extension is not installed automatically

djangonauts/django-hstore,pombredanne/django-hstore,Stranger6667/django-hstore,pombredanne/django-hstore,pombredanne/django-hstore,djangonauts/django-hstore,Stranger6667/django-hstore,Stranger6667/django-hstore,djangonauts/django-hstore,pombredanne/django-hstore,djangonauts/django-hstore,Stranger6667/django-hstore