Add db/schema.rb to version control
[gem] Bump rails version to ~> 4.0.0
[gem] Add gems for extracted Rails features that we use
Add Rails 4 binstubs

`rake rails:update:bin`
Remove last unused traces of vendor/plugins
Updated routes for Rails 4
Update last of Rails 2 find(:all) and find(:first)
Update dynamic find_or_initialize/create for Rails 4
Update old-style .first and .all finders with attributes
Remove config.whiny_nils
Remove config.active_record.auto_explain_threshold_in_seconds
Add config.eager_load settings to environments
[gem] Replace memcache-client with dalli
Remove deprecated use of Relation#all
Update deprecated :confirm option in form/link helpers
Configure JS and CSS compressors for production
Include vendored image, font, and flash assets when precompiling
[migration] Remove ProposalsUser model, use HABTM

We're never using the timestamps stored on the proposals_users join
table, and it makes things simpler to just use a HABTM relationship.
Use Nokogiri to parse ATOM in specs, not ActiveResource
Enable JSON root element, for API consistency