custom_plan.rb

require 'zeus/rails'

ROOT_PATH = File.expand_path(Dir.pwd)
ENV_PATH  = File.expand_path('spec/dummy/config/environment',  ROOT_PATH)
BOOT_PATH = File.expand_path('spec/dummy/config/boot',  ROOT_PATH)
APP_PATH  = File.expand_path('spec/dummy/config/application',  ROOT_PATH)
ENGINE_ROOT = File.expand_path(Dir.pwd)
ENGINE_PATH = File.expand_path('lib/my_engine/engine', ENGINE_ROOT)

class CustomPlan < Zeus::Rails
end

Zeus.plan = CustomPlan.new

zeus.json

{
  "command": "ruby -rubygems -r./custom_plan -eZeus.go",

  "plan": {
    "boot": {
      "default_bundle": {
        "development_environment": {
          "prerake": {"rake": []},
          "runner": ["r"],
          "console": ["c"],
          "server": ["s"],
          "generate": ["g"],
          "destroy": ["d"],
          "dbconsole": []
        },
        "test_environment": {
          "test_helper": {"test": ["rspec", "testrb"]}
        }
      }
    }
  }
}