Remove Tag from Author

[askingalot]

As a blog connoisseur I would like to be able to remove a tag/keyword from an author in the event that it no longer applies. 

Given the user is viewing the Author Details menu
When they select the option to remove a tag
Then they should be presented with the list of the author's tags in order to choose the tag to remove

Given the user chooses a tag to remove
When they type in the selection and hit enter
Then the relationship between the author and the tag should be removed from the database