yeah ... we should be installing the gem :)

app/controllers/users_controller.rb

@@ -454,7 +454,6 @@ class UsersController < ApplicationController
       authenticator.after_create_account(user, auth)
     end
 
-
     def register_nickname(user)
       if user.valid? && SiteSetting.call_discourse_hub?
         DiscourseHub.register_nickname(user.username, user.email)

lib/plugin/instance.rb

@@ -176,7 +176,7 @@ class Plugin::Instance
     unless File.exists? spec_file
       command = "gem install #{name} -v #{version} -i #{gems_path} --no-rdoc --no-ri"
       puts command
-      puts `command`
+      puts `#{command}`
     end
     if File.exists? spec_file
       spec = Gem::Specification.load spec_file