Download button added to metadata box on details page

app/views/packages/_details_rightbox.slim

@@ -31,6 +31,17 @@
     p
       = link_to pkg.homepage, pkg.homepage, target: '_blank'
 
+  // APT package download link
+  hr
+  p.subtitle
+    = fa_icon 'download'
+    '  Install this software package
+    p
+      ' If the package is available for the distribution you are
+      ' currently using on your computer then install the software
+      ' by clicking on…
+    a.button.small.secondary href="apt:#{pkg.name}" Install #{pkg.name}
+
   // statistics
   hr
   p.subtitle