make a separate i18n_tools gem group

This way the i18n:generate rake task can be run from production
environments as well

test plan: run rake i18n:generate, it should still output the new yml
file as before.

Change-Id: I17104686e5c7de3bacbfae9d164a9709182e2499
Reviewed-on: https://gerrit.instructure.com/11557
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>

Gemfile

@@ -102,10 +102,13 @@ group :development do
   else
     gem 'ruby-debug',   '0.10.4'
   end
+  gem 'guard', '1.0.3'
+end
+
+group :i18n_tools do
   gem 'ruby_parser', '2.0.6'
   gem 'sexp_processor', '3.0.5'
   gem 'ya2yaml', '0.30'
-  gem 'guard', '1.0.3'
 end
 
 group :redis do

lib/tasks/i18n.rake

@@ -50,6 +50,7 @@ namespace :i18n do
 
   desc "Verifies all translation calls"
   task :check => :environment do
+    Bundler.require :i18n_tools
     only = if ENV['ONLY']
       ENV['ONLY'].split(',').map{ |path|
         path = '**/' + path if path =~ /\*/