Add feature spec for creating posts

Change-Id: I9e6bacadda427a4d77927ecfb1d45889bbe486c1
Add friendly_id to slug posts

Change-Id: I4a57775b3739565932e8969746710a9be653590f
Use friendly-id history

Does a lookup on historical friendly ID's if we can't get the slug
we're looking for the first time

Change-Id: Ic0d04d9e2e549d89267376c32c9c2ce5b8d50f44
Put posts resource at the root

I think it looks better this way.

Change-Id: I9abcebb39f806dab60958b3603ab673c86bdf84b