Rename Ruby project to Rubygem, make Bundler mutator.

Among other things, this removes some more boilterplate in the
Shantyfile by discovering things when we can.

Shantyfile

@@ -1,10 +1,2 @@
-# FIXME: This shouldn't need to be required, can be auto-discovered.
-require 'shanty/projects/ruby'
-require 'shanty/plugins/bundler'
-require 'shanty/plugins/rspec'
-require 'shanty/plugins/rubocop'
-
-type RubyProject
-plugin ::Shanty::BundlerPlugin
 plugin ::Shanty::RspecPlugin
 plugin ::Shanty::RubocopPlugin

lib/shanty.rb

@@ -4,8 +4,12 @@
 
 require 'shanty/cli'
 require 'shanty/discoverers/shantyfile'
+require 'shanty/discoverers/rubygem'
 require 'shanty/graph'
+require 'shanty/mutators/bundler'
 require 'shanty/mutators/git'
+require 'shanty/plugins/rspec'
+require 'shanty/plugins/rubocop'
 require 'shanty/task_env'
 require 'shanty/task_sets/basic'
 

lib/shanty/discoverers/rubygem.rb

@@ -0,0 +1,17 @@
+require 'shanty/discoverer'
+require 'shanty/projects/rubygem'
+
+module Shanty
+  # Public: Discoverer for Shantyfiles
+  # will create a a project for every Shantyfile it finds in
+  # a directory
+  class RubygemDiscoverer < Discoverer
+    def discover
+      Dir['**/*.gemspec'].map do |path|
+        create_project_template(File.absolute_path(File.dirname(path))) do |project_template|
+          project_template.type = RubygemProject
+        end
+      end
+    end
+  end
+end

lib/shanty/mutators/bundler.rb

@@ -0,0 +1,13 @@
+require 'shanty/mutator'
+require 'shanty/plugins/bundler'
+
+module Shanty
+  # Bundler mutator
+  class BundlerMutator < Mutator
+    def mutate(graph)
+      graph.each do |project|
+        BundlerPlugin.add_to_project(project) if File.exist?(File.join(project.path, 'Gemfile'))
+      end
+    end
+  end
+end

lib/shanty/projects/ruby.rb → lib/shanty/projects/rubygem.rb

@@ -2,7 +2,7 @@
 
 module Shanty
   # Public: Represents a projects created with the Ruby language.
-  class RubyProject < Project
+  class RubygemProject < Project
     subscribe :build, :on_build
 
     def on_build