If you need pagination for a collection in a Jekyll theme, you can use the following Liquid logic which works also on Github pages

pagination-collection.liquid

{% comment %}
#
#   I modified the original code from http://anjesh.github.io/2015/01/25/collection-pagination-working-github-pages/
#
#   Make a collection in _config.yml and create the folder _your_collection in your root.
#
#   collections:
#     your_collection:
#       output: true
#       permalink: /:collection/:title/
#
#
#
{% endcomment %}
{% for c in site.your_collection %}
{% if c.title == page.title %}
  {% assign thisPost = c %}
  {% if forloop.index == 1 %}
    {% assign prevflag = 0 %}
    {% assign nextflag = 1 %}
  {% elsif forloop.index == forloop.length %}
    {% assign prevflag = 1 %}
    {% assign nextflag = 0 %}
  {% else %}
    {% assign prevflag = 1 %}
    {% assign nextflag = 1 %}
  {% endif %}
{% endif %}
{% endfor %}

{% for c in site.your_collection %}
  {% if c.title == page.title %}
    {% assign prevflag = 0 %}
  {% endif %}
  {% if prevflag == 1 %}
    {% assign prevPost = c %}
    {% assign page.previous = c %}
  {% endif %}
{% endfor %}

{% if nextflag == 1 %}
  {% for c in site.your_collection %}
    {% if foundPost == 1 %}
      {% assign getNext = 1 %}
    {% endif %}
    {% if c.title == page.title %}
      {% assign foundPost = 1 %}
    {% endif %}
    {% if getNext == 1%}
      {% assign nextPost = c %}
      {% assign page.next = c %}
      {% assign foundPost = 0 %}
      {% assign getNext = 0 %}
    {% endif %}
  {% endfor %}
{% endif %}

<div id="post-nav">
    {% if prevPost.url %}
    <a class="prev" rel="prev" href="{{ prevPost.url }}">
        <span>&lt; {{ prevPost.title }}</span>
    </a>
    {% endif %}
    {% if nextPost.url %}
    <a class="next" rel="next" href="{{ nextPost.url }}">
        <span>{{ nextPost.title }} &gt;</span>
    </a>
    {% endif %}
</div>

A little cleaner version (no HTML included): Note: Tested only on jekyll

{% assign prevflag = 1 %}
{% assign nextflag = 1 %}

{% for c in site.your_collection %}
  {% if c.title == page.title %}
    {% assign currentItemIndex = forloop.index0 %}
    {% if forloop.index == 1 %}
      {% assign prevflag = 0 %}
      {% assign nextflag = 1 %}
    {% elsif forloop.index == forloop.length %}
      {% assign prevflag = 1 %}
      {% assign nextflag = 0 %}
    {% endif %}
  {% endif %}
{% endfor %}

{% if prevflag == 1 %}
  {% assign prevItemIndex = currentItemIndex | minus: 1 %}
  {% assign prevPost = site.your_collection[prevItemIndex] %}
{% endif %}

{% if nextflag == 1 %}
  {% assign nextItemIndex = currentItemIndex | plus: 1 %}
  {% assign nextPost = site.your_collection[nextItemIndex] %}
{% endif %}

what does "c" mean in this?