def scm(force = false)
      return @_scm if @_scm && !force
      
      case self.config[:scm]
      when :git
        @_scm = Release::Scm::Git.new(:path => self.source_path)
      else
        raise "Unknown SCM #{options[:scm].inspect}"
      end
    end
def scm(force = false)
      return @_scm if @_scm && !force
      
      case self.config[:scm]
      when :git
        @_scm = Release::Scm::Git.new(:path => self.source_path)
      else
        raise "Unknown SCM #{options[:scm].inspect}"
      end
    end
Get the current SCM object