I don't think is quite right; I never hear people say "python django" whereas I do hear "ruby on rails" at least as often as "rails". Note also rails is a general term and django is either the web framework or the jazz artist it is named after.
Not that I think this google trends data really mean that much, I think the following queries give context to help interpret the meaning of the parent's link.
"python, ruby, javascript" http://www.google.de/trends?q=python%2C+ruby%2C+javascript&#...
"django, ruby rails, node.js" http://www.google.de/trends?q=django%2C+ruby+rails%2C+node.j...
"django, Django Reinhardt" http://www.google.de/trends?q=django%2C+Django+Reinhardt+...
[edit, corrected link]
[edit: someone else make the same point several hours ago, and this argument was not persuasive http://news.ycombinator.com/item?id=3277694 I just can't see making a serious decisions based on google search trends unless your job is SEO or something like that]