Rails Form Helper not reading question mark for object attribute - ruby-on-rails

Question

Ruby Version: 2.0
Rails Version: 4.0
I have a controller Question, which has an embedded form for a model Answer.
question.rb
class Question < ActiveRecord::Base
has_many :answers, :dependent => :destroy
accepts_nested_attributes_for :answers, :allow_destroy => true
end
answer.rb
class Answer < ActiveRecord::Base
belongs_to :question
end
answers migration
class CreateAnswers < ActiveRecord::Migration
def change
create_table :answers do |t|
t.string :text
t.integer :question_id
t.boolean :correct?
t.timestamps
end
end
end
in the form, when editing or creating a new question - the user may enter up to 4 possible answers, and mark a check box for the "correct" answer(s).
/views/questions/_form.html.erb
<%= form_for(#question) do |f| %>
<div class="field">
<%= f.label :text %><br>
<%= f.text_area :text %>
</div>
<p>Enter up to 4 posisble answer choices.</p>
<%= f.fields_for :answers do |answer| %>
<div class="field">
<%= answer.text_field :text %>
<%= answer.check_box :correct? %>
</div>
<% end %>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
relevant snippets from questions_controller.rb
def new
#question = Question.new
4.times { #question.answers.build }
end
private
# Use callbacks to share common setup or constraints between actions.
def set_question
#question = Question.find(params[:id])
end
# Never trust parameters from the scary internet, only allow the white list through.
def question_params
params.require(:question).permit(:text, :quiz_id, answers_attributes: [:id, :text, :correct?])
end
Finally - on to my problem
Everything listed above worked perfectly until I added the checkboxes for answer.correct?. When I submit the form as is I get this message in my logs:
Unpermitted parameters: correct
Unpermitted parameters: correct
Unpermitted parameters: correct
Unpermitted parameters: correct
Weird... there is definitely a question mark at the end of that parameter. Allowing this to pass through without the question mark be editing the allowed parameters in the controller gets me this error message:
unknown attribute: correct (this one actually throws an error message, I don't have to go digging in the logs to find this.)
How do I get the form helper to read the question mark?

Answer 1

? is not a valid character for inclusion within a column name. First, create a new database migration:
# from command line
rails generate migration ChangeCorrectInAnswers
Rename your column from correct? to correct:
# in the resulting migration
class ChangeCorrectInAnswers < ActiveRecord::Migration
def up
rename_column :answers, :correct?, :correct
end
end
Run the migration:
# from command line
rake db:migrate
Finally, remove the ? from your field in the view:
# app/views/questions/_form.html.erb
<%= answer.check_box :correct %>