Add Gem::Specification#add_bundler_dependencies for gemspecs

Use like this:

Gem::Specification.new do |s|
  [...the usual...]
  s.add_bundler_dependencies
end

The generated gemspec will contain dependencies on your bundler gems,
and gems in the bundler group :development will be added as dev deps.

1 files changed, 10 insertions, 0 deletions

diff --git a/lib/bundler/rubygems_ext.rb b/lib/bundler/rubygems_ext.rb
index f93c5ccc46..c1d5a45939 100644
--- a/lib/bundler/rubygems_ext.rb
+++ b/lib/bundler/rubygems_ext.rb
@@ -31,6 +31,16 @@ module Gem
       gemfile << dependencies_to_gemfile(development_dependencies, :development)
     end
 
+    def add_bundler_dependencies
+      Bundler.definition.dependencies.each do |dep|
+        if dep.groups.include?(:development)
+          self.add_development_dependency(dep.name, dep.requirement.to_s)
+        else
+          self.add_dependency(dep.name, dep.requirement.to_s)
+        end
+      end
+    end
+
   private
 
     def dependencies_to_gemfile(dependencies, group = nil)