Add assignee directly in Agile New Story Dialog

[#1]

I would like to request the ability to assign an assignee(s) while creating a new story. By default, it should assign the story to the person creating the story. The reason why this is important is because currently, a new story is not assigned to anyone after creation. This "loses" the story in the list of stories. By requiring an assignee to the story, even defaulting to the creator, it'll help avoid the situation of a new story getting buried in a large set of stories.