trying to get Heroku working
heroku setup script
add params to db/seed.rb; provide better heroku login detection
Merge remote-tracking branch 'origin/master' into heroku
trying a custom buildpack to customize Procfile
Gemfile trickery for Heroku
try again
exit when username is wrong
adding a basic RSS agent
Make {{agent}} universally accessible from any agent.

To implement this, EventDrop is introduced to represent an Event object
in interpolation.
Add a hover-help for the Options field which explains interpolation.
EventFormattingAgent: Partial revert: Do not include "agent" to payload.
Introduce a new concern LiquidDroppable for refactoring.
Improve agents diagram.

- Fold each agent name after every 20+ characters.

- Choose the rounded box as node shape.

- Signify disabled agents with gray color, including arrows.

- Use a shorter node name to shorten code that often exceeds the limit
  of Google Chart API when an agent with a long name has lots of sources
  and receivers.

- Use a smaller font size, and specify Helvetica as font family in SVG
  output to match the rest of the site contents.
Set the link target of nodes to _blank.
Merge pull request #407 from cantino/rss_agent

adding a basic RSS agent
Merge pull request #413 from knu/improve_diagram

Improve agents diagram.
Merge pull request #404 from cantino/heroku

Heroku deployment!
Update README.md
Merge pull request #410 from knu/provide_access_to_agent

EventFormattingAgent: Provide access to upstream agent