Create relationship between author and post

Author was an attribute of a post rather than it's own object. Author
as its own object allows for normalization of the data and increased
control and functionality over the Author data. Users will no longer
have to add the author attribute each time author is used. Printing of
the author name was also made more efficient.

Dan Buttig @dbuttig <daniel.buttig@gmail.com>
Amos King @adkron <amos.l.king@gmail.com>