slidedown gem should depend on open4 gem

[cout]

I had to install the open4 gem manually to get slidedown to run.

[nakajima]

What version are you using? We're currently using open3, which doesn't require a gem install.

[cloudhead]

same here.

ruby 1.9.1
slidedown 0.2.0

[telemachus]

Same here. open4 was necessary both on 1.8.7-p302 and on 1.9.2-p0 (OSX 10.6.4, if that's relevant).

Relevant gems:

bluecloth (2.0.7)
makers-mark (0.1.1)
nokogiri (1.4.3.1)
open4 (1.0.1)
slidedown (0.2.0)

[Endle]

ruby 2.0.0p353
Need to install open4 manually