Render feeds

[chris34]

• [x] Ikhaya: done in #110
• [x] Forum
• [x] Planet → already included

• [ ] Wiki → template does not exist yet → #144

  [chris@Arch theme-ubuntuusers]$ grep -r "set feed" inyoka_theme_ubuntuusers/templates/
  inyoka_theme_ubuntuusers/templates/ikhaya/index.html:  {% set feeds = [
  inyoka_theme_ubuntuusers/templates/ikhaya/index.html:  {% set feeds = [
  inyoka_theme_ubuntuusers/templates/ikhaya/detail.html:{% set feed = 'feeds/comments/%s/%%s/20'|format(article.id) %}
  inyoka_theme_ubuntuusers/templates/ikhaya/detail.html:{% set feeds = [
  inyoka_theme_ubuntuusers/templates/wiki/action_log.html:{% set feeds = [
  inyoka_theme_ubuntuusers/templates/forum/topic.html:{% set feeds = [
  inyoka_theme_ubuntuusers/templates/forum/index.html:  {% set feeds = [
  inyoka_theme_ubuntuusers/templates/forum/forum.html:{% set feeds = [
  inyoka_theme_ubuntuusers/templates/planet/index.html:{% set feeds = [

also depends on #110