Add Open Graph data for group, project and commit.

app/helpers/page_layout_helper.rb

@@ -53,6 +53,8 @@ module PageLayoutHelper
       @project.avatar_url || default
     elsif @user
       avatar_icon(@user)
+    elsif @group
+      @group.avatar_url || default
     else
       default
     end

app/views/groups/show.html.haml

+- page_description @group.description
+
 - unless can?(current_user, :read_group, @group)
   - @disable_search_panel = true

app/views/layouts/_head.html.haml

+- site_name = "GitLab"
 %head{prefix: "og: http://ogp.me/ns#"}
   %meta{charset: "utf-8"}
   %meta{'http-equiv' => 'X-UA-Compatible', content: 'IE=edge'}
-  %meta{name: 'referrer', content: 'origin-when-cross-origin'}
-
-  %meta{name: "description", content: page_description}
   -# Open Graph - http://ogp.me/
   %meta{property: 'og:type',        content: "object"}
-  %meta{property: 'og:site_name',   content: "GitLab"}
+  %meta{property: 'og:site_name',   content: site_name}
   %meta{property: 'og:title',       content: page_title}
   %meta{property: 'og:description', content: page_description}
   %meta{property: 'og:image',       content: page_image}
@@ -20,8 +18,9 @@
   %meta{property: 'twitter:image',        content: page_image}
   = page_card_meta_tags
-  - page_title "GitLab"
+  - page_title site_name
   %title= page_title
+  %meta{name: "description", content: page_description}
   = favicon_link_tag 'favicon.ico'
@@ -34,6 +33,7 @@
   = include_gon
+  %meta{name: 'referrer', content: 'origin-when-cross-origin'}
   %meta{name: 'viewport', content: 'width=device-width, initial-scale=1, maximum-scale=1'}
   %meta{name: 'theme-color', content: '#474D57'}

app/views/projects/commit/show.html.haml

-- page_title "#{@commit.title} (#{@commit.short_id})", "Commits"
+- page_title        "#{@commit.title} (#{@commit.short_id})", "Commits"
+- page_description  @commit.description
+
 = render "projects/commits/header_title"
 = render "commit_box"
 - if @ci_commit

app/views/projects/show.html.haml

+- page_description @project.description
+
 = content_for :meta_tags do
   - if current_user
     = auto_discovery_link_tag(:atom, namespace_project_path(@project.namespace, @project, format: :atom, private_token: current_user.private_token), title: "#{@project.name} activity")