Fixed typo on README.rst
Fixed typo on README.rst

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