Fel:Inkompatibla teckenkodningar:UTF-8 och ASCII-8BIT

Jag har samma problem, och jag löste det efter timmars sökning med en appatch.

    module ActiveSupport #:nodoc:
      class SafeBuffer < String

        def safe_concat(value)
          value = force_utf8_encoding(value)
          raise SafeConcatError unless html_safe?
          original_concat(value)
        end

        def concat(value)
          value = force_utf8_encoding(value)
          if !html_safe? || value.html_safe?
            super(value)
          else
            super(ERB::Util.h(value))
          end
        end

        alias << concat

        private

        def force_utf8_encoding(value)
          self.force_encoding('UTF-8').html_safe unless self.encoding.name == 'UTF-8'
          value = (value).force_encoding('UTF-8').html_safe unless value.nil? || value.encoding.name == 'UTF-8'
          value
        end
      end
    end