Froala

This assume you want to use the FREE version of Froala Editor (which shows their badge in the editor). For more information, please see: http://www.froala.com/

How to use:

1. Add Froala's assets gem.

Note: This functionality is currently available in the master branches of both rails_admin and froala/wysiwyg-rails, but neither gem has released a version with these features. For now, we'll need to use specific revisions of these gems from GitHub:

gem "rails_admin", github: "sferik/rails_admin", ref: "43f368a" # pending release of > 0.6.7
gem "wysiwyg-rails", github: "froala/wysiwyg-rails", ref: "8daf0c3" # pending release of > 1.2.6

2. Enabling froala editor for your field is easy

edit do
  field :content, :froala
end

# Optionally providing froala options (see https://editor.froala.com/options)
edit do
  field :content, :froala do
    config_options {
      inlineMode: false,
      paragraphy: false
    }
  end
end

More here and here