Add this line to your application's Gemfile:

gem 'activeadmin_simplemde'

And then execute:

$ bundle

Or install it yourself as:

$ gem install activeadmin_simplemde

• Add at the end of your ActiveAdmin styles (app/assets/stylesheets/active_admin.scss):

@import 'active_admin/simplemde';

• Add at the end of your ActiveAdmin javascripts (app/assets/javascripts/active_admin.js):

//= require active_admin/simplemde/simplemde
//= require active_admin/simplemde_editor_input

• Use the input with as: :simplemde_editor in Active Admin model conf

# ActiveAdmin article form conf:
  form do |f|
    f.inputs 'Article' do
      f.input :title
      f.input :description, as: :simplemde_editor
      f.input :published
    end
    f.actions
  end

If you use this component just star it. A developer is more motivated to improve a project when there is some interest.

Bug reports and pull requests are welcome on GitHub at https://github.com/YevheniiPylypenko/activeadmin_simplemde.

The gem is available as open source under the terms of the MIT License.