Switch gender, ethnicity to free text fields.

I'm wary of forcing people to use a specific set of results for both gender and ethnicity (though this is a relatively recent awareness, the credit really goes to @cczona and @megahbite). This patch changes both of those fields to text inputs instead of selects - people can describe themselves as they see fit, instead of feeling obliged to fit into a specific box (or the fallback of an 'Other' option).

Further context here: http://www.slideshare.net/cczona/schemas-for-the-real-world-rubyconf-au-201302