Update comment from /mentors/applications/:id page

app/controllers/mentors/comments_controller.rb

@@ -7,7 +7,7 @@ def create
     end
 
     def update
-      comment = mentor_comments.update(params[:id], update_params)
+      comment = mentor_comments.update(params[:mentor_comment][:commentable_id], update_params)
       redirect_to path_for(comment)
     end
 
@@ -20,7 +20,7 @@ def create_params
     end
 
     def update_params
-      params.require(:mentor_comment).permit(:text)
+      params.require(:mentor_comment).permit(:id, :text)
     end
 
     def path_for(comment)

app/views/mentors/applications/_comment.html.slim

@@ -1,7 +1,8 @@
 hr(id="#{dom_id comment}")
-= simple_form_for comment, url: mentors_comments_path do |f|
+= simple_form_for comment, :url => comment.new_record? ? url_for(action: 'create', controller: 'mentors/comments') :url_for(action: 'update', controller: 'mentors/comments') do |f|
   .form-inputs.clearfix
     = f.input :commentable_id, as: :hidden, value: comment.commentable_id
+    = f.input :id, as: :hidden, value: comment.id
     = f.input :text, as: :text, label: 'My Comment', input_html: { rows: 5 }, hint: 'This is a place for you to take notes for yourself about this application. Your comment is only visible to yourself as well as the selection committee and you can update and remove it as you like.'
   .form-actions
     = f.button :submit

spec/controllers/mentors/comments_controller_spec.rb

@@ -74,7 +74,7 @@
 
       context 'when comment exists' do
         let!(:comment) { Mentor::Comment.create(user: user, commentable_id: 1, text: 'something') }
-        let(:params)   {{ id: comment.id, mentor_comment: { text: 'something else' } }}
+        let(:params)   {{ id: comment.id, mentor_comment: { text: 'something else', commentable_id: comment.id } }}
 
         subject { put :update, params: params }