Add statistic for duration standard deviation
Add method to predict the lower and upper bound on deploy ETA
Add completion bounds to the API
Add simple text description of predictions to deploy details page

This UI is atrocious.
Expose std dev stats
Use more specific method name
Compare std dev implementation for sql and Ruby stats
Inherit from StepStatistics to reduce method duplication
Use SqlStepStatistics for predictions
Merge branch 'rework_predictions'

Add bounds to deploy predictions without terrible performance impact.
The UI is currently terrible.

  GET /api/deploys/:id

  Without predictions (all times in seconds)
  0.0063
  0.0039
  0.0033
  0.0034
  0.0036

  With predictions, using StepStatistics
  0.2440
  0.2659
  0.2816
  0.2434
  0.2795

  With predictions, using SqlStepStatistics
  0.0456
  0.0425
  0.0425
  0.0429
  0.0519
Add views helper to output data-updated-at attr
Embed initial timestamp when rendering active deploy view on server. Fixes #5.
Use data_updated_at helper
Extract constant for default secs to consider when updated_at is not specified
Merge branch 'fix_non_updating_deploy_pages'
Merge remote-tracking branch 'origin/master' into lock_deploys
Add FontAwesome

Font Awesome by Dave Gandy
http://fortawesome.github.com/Font-Awesome
Rename duplicate migration
Add index to migration
Change lock to accept description param directly