Fix back buttons on the edit pages- redmine task 2172

While going through the changes I made on the browser, I noticed some URLs are showing errors.

http://localhost:3000/traits/219/edit
http://localhost:3000/variables/
http://localhost:3000/posteriors/1/edit

I do not think they are related to my changes though.
This marker indicates that there is a missing newline at the end of the file.  It is preferred that all files end with a newline character.