Made it this way so that I can use the PostAndCommentService as a child
of the PostService and CommentService.
Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>
Some functionality such as saving, voting, deleting, etc. is common to
both posts and comments, so this service will hold such methods.
Tweaked the separate post/comment services accordingly. Fixed tests.
Signed-off-by: Vartan Benohanian <vartanbeno@gmail.com>