Make yum download instructions more dyanamic

Using the crawled data, propulate dropdown boxes with versions and
platforms, to be able to show simpler instructions of exactly which
commands to use to install using the yum repository.

pgweb/downloads/views.py

@@ -192,6 +192,13 @@ def mirrorselect(request, path):
 	return HttpResponseRedirect("https://ftp.postgresql.org/pub/%s" % path)
 
 
+# Render javascript for yum downloads
+def yum_js(request):
+	with open(settings.YUM_JSON) as f:
+		jsonstr = f.read()
+	return render_to_response('downloads/js/yum.js', {
+		'json': jsonstr,
+		}, content_type='application/json')
 
 #######
 # Product catalogue