AC: guests cannot write stories

- T: scaffold stories model
AC: link to create stories from the navbar

- fix improper nesting in navbar partial
AC: title is required
T: add ruby version to gemfile
AC: body is required
AC: Author is required
I: fix navbar layout for admins

[closes #3]
I: add :admin role to Story.attr_accessible

[closes #2]
Merge pull request #1 from koedbymonkey/stories/6001

S: As a User ISBAT write stories