Error in liquid syntax for posts_by_tag.md

[mechatour]

When starting the jekyll server error is:

Liquid Warning: Liquid syntax error (line 1): Expected dotdot but found pipe in "{{(site.tags | sort:0) }}" in posts_by_tag.md

Syntax should be on first line after front matter:

{% assign sorted_tags = site.tags | sort %}

Hope this helps. Keep up the great work!