We should be able to install specific versions of gems, and accuratel…

…y install the required versions of their dependencies.

lib/rip/packages/remote_gem_package.rb

@@ -16,7 +16,7 @@ def fetch!
 
       Dir.chdir cache_path do
         ui.puts "Installing #{source} via Rubygems..."
-        unless Sh::Gem.fetch(source)
+        unless Sh::Gem.fetch(source, version)
           FileUtils.rm_rf cache_path
           ui.abort "Couldn't find gem #{source} in any of your gem sources"
         end
@@ -35,12 +35,16 @@ def dependencies!
     end
 
     def version
-      actual_package ? actual_package.version : super
+      local_gem ? actual_package.version : @version
     end
 
     memoize :actual_package
     def actual_package
-      Package.for(Dir[cache_path + '/*'].first)
+      Package.for(local_gem)
+    end
+
+    def local_gem
+      Dir[cache_path + '/*'].first
     end
   end
 end

lib/rip/sh/gem.rb

@@ -22,8 +22,10 @@ def exists?(name)
         @@exists_cache[name] ||= rgem("search #{name} --remote").split("\n").select { |f| f =~ /^#{name} / }.any?
       end
 
-      def fetch(name)
-        rgem("fetch #{name}") =~ /Downloaded (.+)/
+      def fetch(name, version=nil)
+        source_string = name
+        source_string += " --version '#{version}'" if version
+        rgem("fetch #{source_string}") =~ /Downloaded (.+)/
       end
 
       def dependencies(path_to_gem)