Decko: you hold the cards

Gem Version Semaphore Build Code Climate Badge License: GPL v3


Decko (formerly “Wagn”) makes elegant web development fun.

Install a new deck, and you can immediately open a browser and start collaborating on content, design, and structure. Decko creators, or “Card Sharks”, use Decko to create open community sites, private knowledge management sites, project management systems, wikis, blogs, journals, forums, and more.

Ruby developers can take these creations even further with Decko’s development framework. As a Decko “Monkey”, you can use the innovative Mods API to create sophisticated web systems that integrate seamlessly with structures that “Sharks” create on the site.

Start Sharking

Installation help is below. And there’s lots of info at, including:

And info about contributing to Decko is right next door.

Start Monkeying

On our docs site:

Elsewhere on Github: - optional mods

We also have API Docs on Swaggerhub.


1. install dependencies

requirement variants
Ruby 2.5+
Bundler 1.0+
ImageMagick 6.7.8+
A database engine MySQL (5.7+) or PostgreSQL (9.4+)
A JavaScript runtime Node.js (8.9+) or other

2. install the gem

gem install decko

Watch carefully for errors!

3. create a new deck

decko new MY_DECK

MY_DECK is, of course, a variable. Use any name you like.


-f, [--force]                            # Overwrite files that already exist
-p, [--pretend], [--no-pretend]          # Run but do not make any changes
-q, [--quiet], [--no-quiet]              # Suppress status output
-s, [--skip], [--no-skip]                # Skip files that already exist
-M, [--monkey], [--no-monkey]            # Prepare deck for monkey (mod developer)
-P, [--platypus], [--no-core-dev]        # Prepare deck for platypus (core developer)
-R, [--repo-path=PATH]                   # Path to local decko repository.
                                         # Can also specify via `env DECKO_REPO_PATH=PATH`
-I, [--interactive], [--no-interactive]  # Prompt with dynamic installation options

4. create / seed database

Edit the config/database.yml file as necessary. More about database configuration at

Then run

decko setup create and seed the database


-p, --production                 decko:seed production database (default)
-t, --test                       decko:seed test database
-d, --development                decko:seed development database
-a, --all                        decko:seed production, test, and development database

5. start your server

To fire up the default, built-in WEBrick server, just run:

decko server

…and point your browser to http://localhost:3000 (unless otherwise configured).


-p, [--port=port]                        # Runs Decko on the specified port. 
                                           Defaults to 3000.
-b, [--binding=IP]                       # Binds Decko to the specified IP.
                                           Defaults to 'localhost' in development 
                                           and '' in other environments'.
-c, [--config=file]                      # Uses a custom rackup configuration.
                                           Default is
-d, [--daemon], [--no-daemon]            # Runs server as a Daemon.
-e, [--environment=name]                 # Specifies the environment in which to run 
                                           this server (development/test/production).
-P, [--pid=PID]                          # Specifies the PID file.
                                           Default is tmp/pids/
    [--early-hints], [--no-early-hints]  # Enables HTTP/2 early hints.

For more information, see


Standard Upgrade

1. Backups

Always back up your database and uploaded files.

2. Update Libraries

From your decko root directory run:

bundle update

3. Update Database

Run the following:

decko update

4. Restart your server.

Upgrade from Wagn to Decko

If you have an old site (pre 2018), haven’t upgraded in a long time, and see many references to “Wagn” in your deck, you may need to do a more involved update.

1. update references to “wagn” in file content

In your decko’s root directory, edit Gemfile, config/application.rb, config/routes.rb, and script/wagn, replacing “wagn” with “decko”. (Keep the same capitalization pattern.)

2. update references to “wagn” in file names.

From your decko root directory run:

mv script/wagn script/decko

3. continue as with Standard Upgrade

See above.

Upgrade pre-gem Wagn site

First check the Wagn version of your existing site.

Version 1.10 or newer

  1. Create a new deck using steps 1 and 2 from the installation section above.
  2. Copy config/database.yml from the old site to the new one.
  3. Copy the old local/files contents to the new files directory.
  4. If you have edited wagn.yml in your old site, make the corresponding changes to the new config/application.rb file.
  5. Follow the standard upgrade procedure above.

Older than Version 1.10

Ho. Ly. Cow. Welcome back!

First update your Wagn to version 1.10 via the old update mechanisms, and then follow the directions above.


Mods are little bits of code that alter Decko behavior.

Installing Mods

Many mods have been made into ruby gems that follow the naming pattern card-mod-X. All you have to do to install one of these mods is:

1. add the mod (or mods) to your Gemfile

 gem "card-mod-mymod"

2. download and install the gem

 bundle update

3. run any migrations, mergers, or scripts:

 decko update

…and then restart your server.

Creating / Editing mods

Development Environment

If you’re interested in making your own mod, the first thing to do is set up a good development environment. This is most easily done by creating a new deck with the --monkey (or -M) options, eg:

decko new MY_DECK --monkey

If you’re working on an existing deck, it’s often easiest just to do the above and then make the new deck use your existing files and database. However, if that’s not an option, you can instead follow the following procedure:

  1. Make sure you have all the monkey-friendly gems in your Gemfile. If your deck was generated recently, you’ll probably already have several references to these gems (eg card-mod-monkey) and will just need to uncomment them. If not, you can run the above command to create a dummy deck and copy the Gemfile over to your real one.
  2. In your real deck, comment out ENV['RAILS_ENV'] ||= 'production' in config/boot.rb. This will mean your default mode is now “development.”
  3. Configure config/database.yml to your liking.