Add categories to posts

https://trello.com/c/XZllJLO5
Fix broken /admin/people/new
Add employee flag to people table
Don't display broken image if none is available

https://trello.com/c/LygpDMgm
Merge branch 'guest-blog-posts'

* guest-blog-posts:
  Don't display broken image if none is available
  Add employee flag to people table
Move leaflet-rails (map embedding) into gaslight site from training, locking version due to bug in 0.7.4

Error in 0.7.4 is "No value provided for variable {s}, similar to issue at https://github.com/Leaflet/Leaflet/issues/1871, not present in 0.7.3
Fix embedded map on course show page
Load blog engine application helper

I have no idea how this is working in production but is no longer 
working on my machine.
Change precompiled asset path from training_app
Remove fixed width on post images
Update training app reference to pick up image_url delegation to parent course
Revert "Update training app reference to pick up image_url delegation to parent course"

This reverts commit ccf8557aedfaab4db16d59e3f82ef8a402fedb0c. Something in the asset precompile is failing related to heroku and glib.
Only pull employees on PeopleController#show
Move brand assets to public folder
I find this easier to read
Fix broken navigation highlighting

https://trello.com/c/rTltgleZ
Move alignment class out of blog
First pass through on new style for /blog
Design tweaks for mobile
Separate post and post-preview style