enable/disable plugins by config option

lib/foodsoft_wiki/README.md

@@ -14,5 +14,8 @@ gem 'acts_as_versioned', git: 'git://github.com/technoweenie/acts_as_versioned.g
 gem 'foodsoft_wiki', path: 'lib/foodsoft_wiki'
 ```
 
+This plugin introduces the foodcoop config option `use_wiki`, which can be set
+to `false` to disable the wiki. May be useful in multicoop deployments.
+
 This plugin is part of the foodsoft package and uses the GPL-3 license (see
 foodsoft's LICENSE for the full license text).

lib/foodsoft_wiki/app/controllers/pages_controller.rb

@@ -1,5 +1,6 @@
 # encoding: utf-8
 class PagesController < ApplicationController
+  before_filter -> { require_plugin_enabled FoodsoftWiki }
 
   skip_before_filter :authenticate, :only => :all
   before_filter :only => :all do

lib/foodsoft_wiki/lib/foodsoft_wiki.rb

@@ -5,4 +5,9 @@ require 'content_for_in_controllers'
 require 'foodsoft_wiki/engine'
 
 module FoodsoftWiki
+  # Return whether the wiki is used or not.
+  # Enabled by default since it used to be part of the foodsoft core.
+  def self.enabled?
+    FoodsoftConfig[:use_wiki] != false
+  end
 end

lib/foodsoft_wiki/lib/foodsoft_wiki/engine.rb

@@ -1,6 +1,7 @@
 module FoodsoftWiki
   class Engine < ::Rails::Engine
     def navigation(primary, ctx)
+      return unless FoodsoftWiki.enabled?
       primary.item :wiki, I18n.t('navigation.wiki.title'), '#', id: nil do |subnav|
         subnav.item :wiki_home, I18n.t('navigation.wiki.home'), ctx.wiki_path, id: nil
         subnav.item :all_pages, I18n.t('navigation.wiki.all_pages'), ctx.all_pages_path, id: nil