Allow to specify the license of the cover image for each page

source/author.html.haml

@@ -1,7 +1,8 @@
 ---
 pageable: true
-cover: cover.jpg
 per_page: 6
+cover: cover.jpg
+cover_license: "[CC Zero 1.0](https://unsplash.com/license) by [José Martín](https://unsplash.com/photos/45sjAjSjArQ)"
 ---
 
 %header.main-header.author-head{cover}

source/impressum.md.erb

@@ -2,7 +2,8 @@
 title: Impressum
 lang: :de
 layout: page
-cover: impressum/cover.jpg # https://unsplash.com/photos/E0Spm6XXn2Y
+cover: impressum/cover.jpg
+cover_license: "[CC Zero 1.0](https://unsplash.com/license) by [Sergei Zolkin](https://unsplash.com/photos/E0Spm6XXn2Y)"
 ---
 
 Holger Just<br>

source/index.html.haml

@@ -1,6 +1,7 @@
 ---
 pageable: true
 cover: cover.jpg
+cover_license: "[CC Zero 1.0](https://unsplash.com/license) by [José Martín](https://unsplash.com/photos/45sjAjSjArQ)"
 ---
 
 %header.main-header{cover}

source/layouts/layout.haml

@@ -50,5 +50,8 @@
           = link_to 'Impressum', '/impressum/'
         %section.license
           = partial("licenses/#{current_page.data.license || blog_settings.default_license}")
+          - if current_page.data.cover_license.present?
+            | Cover image
+            = markdown(current_page.data.cover_license, true)
 
     = javascript_include_tag :application

source/tag.html.haml

@@ -2,6 +2,7 @@
 pageable: true
 per_page: 6
 cover: cover.jpg
+cover_license: "[CC Zero 1.0](https://unsplash.com/license) by [José Martín](https://unsplash.com/photos/45sjAjSjArQ)"
 ---
 
 %header.main-header.tag-head{cover}