In your code, your options_for_select()
call sets the selected value to "gender" and does not attempt to use the value from your form object.
Please see the docs for options_for_select()
for usage examples.
options_for_select(['Mare', 'Stallion', 'Gelding'], f.object.gender)
options_for_select(['Mare', 'Stallion', 'Gelding'], :selected => f.object.gender)
Alternatively, you can do this, which will already use the gender()
value for your form object:
<%= f.select :gender, ['Mare', 'Stallion', 'Gelding'] %>