Add option to skip migrations

In some cases (in particular, the solidus install) it makes sense
to skip the entire migration block. With the current setup, it's
impossible to not run migrations AND not be asked if you want to
run migrations. This allows for a complete skip of the migrations
+ the question asking part, which will smooth out the Solidus installation.

Author: seand7565

lib/generators/solidus/auth/install/install_generator.rb

@@ -5,6 +5,7 @@ module Auth
     module Generators
       class InstallGenerator < Rails::Generators::Base
         class_option :auto_run_migrations, type: :boolean, default: false
+        class_option :skip_migrations, type: :boolean, default: false
 
         def self.source_paths
           paths = superclass.source_paths
@@ -21,6 +22,8 @@ def add_migrations
         end
 
         def run_migrations
+          return if options[:skip_migrations]
+
           run_migrations = options[:auto_run_migrations] || ['', 'y', 'Y'].include?(ask('Would you like to run the migrations now? [Y/n]'))
           if run_migrations
             run 'bundle exec rake db:migrate'