[bundle] Oops, move trunk plugin to right gem group.

Gemfile

@@ -6,9 +6,6 @@ end
 gemspec
 
 group :development do
-  # Only while we test the trunk app.
-  gem 'cocoapods-trunk', :git => "https://github.com/alloy/cocoapods-trunk.git"
-
   # To develop the deps in tandem use the `LOCAL GIT REPOS` feature of Bundler.
   # For more info see http://bundler.io/git.html#local
   gem 'cocoapods-core',       :git => "https://github.com/CocoaPods/Core.git", :branch => 'master'
@@ -33,6 +30,9 @@ group :development do
 end
 
 group :debugging do
+  # Only while we test the trunk app.
+  gem 'cocoapods-trunk', :git => "https://github.com/alloy/cocoapods-trunk.git"
+
   gem "rb-fsevent"
   gem "kicker", :git => "https://github.com/alloy/kicker.git", :branch => "master"
   gem "awesome_print"