Let's add RESTful routes for notes.

config/routes.rb

resources :notes

Create NotesController with new and edit actions.

app/controllers/notes_controller.rb

class NotesController < ApplicationController
  def new
    @note = Note.new
  end

  def edit
    @note = Note.find params[:id]
  end

Create the views for new and edit, each rendering a form partial.

app/views/notes/new.html.erb and app/views/notes/edit.html.erb

<%= render 'form' %>

The form partial needs to include a text field for title and a textarea for body_html.

_app/views/notes/form.html.erb

<%= form_for @note do |f| %>
  <p>
    <%= f.text_field :title %>
  </p>
  <p>
    <%= f.text_area :body_html %>
  </p>
  <div class="form-actions">
    <%= f.submit class: 'btn btn-default' %>
  </div>
<% end %>

Add create and update actions to the controller, once again using locale-based flash messages.

app/controller/notes_controller.rb

def create
  @note = Note.new note_params
  if @note.save
    flash.now[:notice] = t('note.flash.create.success')
    render :edit
  else
    flash.now[:alert] = t('note.flash.create.failure')
    render :new
  end
end

def update
  @note = Note.find params[:id]
  if @note.update note_params
    flash.now[:notice] = t('note.flash.update.success')
  else
    flash.now[:alert] = t('note.flash.update.failure')
  end
  render :edit
end

config/locales/en.yml

note:
    flash:
      create:
        success: "Your note has been created!"
        failure: "There was a problem creating your note."
      update:
        success: "Saved!"
        failure: "There was a problem saving your changes."

Can you create and update notes if you browse directly to the new and edit paths? Commit!

$ git add .
$ git commit -m "Create and update notes."