(back ported from jekyll/jekyll#3969)

Hi,

until today, I was using the jekyll gem but I wanted to try the new github-pages gem, so I followed the doc and installed it. It updated my gems and after that my jekyll build didn't work anymore:

$ jekyll build
Configuration file: /home/jp/src/perso/barreverte.github.io/_config.yml
            Source: /home/jp/src/perso/barreverte.github.io
       Destination: /home/jp/src/perso/barreverte.github.io/_site
      Generating... 
  Liquid Exception: incompatible character encodings: UTF-8 and ASCII-8BIT in _posts/2012-08-27-binomer-avec-un-clavier-dvorak-et-un-clavier-azerty.markdown
jekyll 2.4.0 | Error:  incompatible character encodings: UTF-8 and ASCII-8BIT

But this post is online since 2012 (see http://www.barreverte.fr/binomer-avec-un-clavier-dvorak-et-un-clavier-azerty/ and its source: https://github.com/barreverte/barreverte.github.io/blob/master/_posts/2012-08-27-binomer-avec-un-clavier-dvorak-et-un-clavier-azerty.markdown)

I removed this post, just to test, and another one post failed for the same reason. I feared I had to destroy a lot of posts to be back on track, so I stopped there.

I created a travis build that shows the issue: https://travis-ci.org/barreverte/barreverte.github.io/ (see broken build https://travis-ci.org/barreverte/barreverte.github.io/builds/84308129 for instance)

I also tried with jekyll/docker and it also failed.

After a lot of searching, the issue was related to jekyll-gist and only 2 files were with problems. In both cases, I replaced the gist commands in these files (but a lot remain in other posts) and the site builds:

• in my local jekyll
• in my docker jekyll
• on travis-ci: https://travis-ci.org/barreverte/barreverte.github.io/builds/85153335

see commit barreverte/barreverte.github.io@3eda156