Bump Rails to v3.2.12
Bump Ruby to patch level 385

@bkeepers,et al:
This is a complete aside, but ... nodeincrease in the
severity, scale, and frequency we ought not trust in tools
that silently modify our environments. IMHO, this file should be removed
entirely.
Fix invite fulfilling
Remove .ruby-version
Extract PublicKey/PrivateKey classes
Expose app in models and collections

This prevents having to pass around references to variables. It's not the best pattern, but for now it simplifies things. We can figure out a cleaner way to expose the keypair later.
Nasty hack to make sharing work.
Add Mega article to reading section
Update schema with defaults
Move fixture helper into a module
Move key features into rpsec
Use database cleaner in specs
Move item feature to rspec
Always clean db with truncation
Use Postgres as the database
Convert public_key to a text field
Configure postgres on travis
Merge branch 'postgres' into rspec-acceptance

* postgres:
  Configure postgres on travis
  Convert public_key to a text field
  Use Postgres as the database
Add launchy and pry for debugging
Remove cucumber