fixed some grammar mistakes
fixed some grammar mistakes

dgk/django-business-logic,dgk/django-business-logic,vlfedotov/django-business-logic,vlfedotov/django-business-logic,dgk/django-business-logic,vlfedotov/django-business-logic,dgk/django-business-logic,dgk/django-business-logic,vlfedotov/django-business-logic,vlfedotov/django-business-logic