Serve a file if in wiki.

app/controllers/projects/wikis_controller.rb

@@ -15,6 +15,17 @@ class Projects::WikisController < Projects::ApplicationController
     if @page
       render 'show'
+    elsif file = @project_wiki.wiki.file(params[:id], @project_wiki.wiki.ref, true)
+       if file.on_disk?
+         send_file file.on_disk_path, :disposition => 'inline'
+       else
+          send_data(
+            file.raw_data,
+            type: file.mime_type,
+            disposition: 'inline',
+            filename: file.name
+          )
+       end
     else
       return render('empty') unless can?(current_user, :write_wiki, @project)
       @page = WikiPage.new(@project_wiki)