Add imagekit
Change to MEDIA_ROOT
Add photo fields
Add photo section
Add photos
Add docs for images
Add photo to Post model

Add third-party django-imagekit. Add a field to Post name photo,
three ImageSpecFields, and an alt text field for photo. Created fields
on the admin to deal with photos and docs about dealing with images.
Also change settings.MEDIA_DIRS to settings.MEDIA_ROOT.
Improve formatting