Fix the install generator

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

@@ -111,14 +111,20 @@ def configure_application
       end
     end
 
-    def install_default_plugins
+    def plugin_install_preparation
+      @plugins_to_be_installed = []
+      @plugin_generators_to_run = []
+    end
+
+    def install_auth_plugin
       if options[:with_authentication] && (options[:auto_accept] || !no?("
-  Solidus has a default authentication extension that uses Devise.
-  You can find more info at https://github.com/solidusio/solidus_auth_devise.
+        Solidus has a default authentication extension that uses Devise.
+        You can find more info at https://github.com/solidusio/solidus_auth_devise.
 
-  Would you like to install it? (y/n)"))
+        Would you like to install it? (y/n)"))
 
-        gem 'solidus_auth_devise'
+        @plugins_to_be_installed << 'solidus_auth_devise'
+        @plugin_generators_to_run << 'solidus:auth:install'
       end
     end
 
@@ -135,7 +141,10 @@ def install_payment_method
 
       gem_name = PAYMENT_METHODS.fetch(name)
 
-      gem gem_name if gem_name
+      if gem_name
+        @plugins_to_be_installed << gem_name
+        @plugin_generators_to_run << "#{gem_name}:install"
+      end
     end
 
     def include_seed_data
@@ -156,6 +165,19 @@ def create_database
       rake 'db:create'
     end
 
+    def run_bundle_install_if_needed_by_plugins
+      @plugins_to_be_installed.each do |plugin_name|
+        gem plugin_name
+      end
+
+      bundle_cleanly{ run "bundle install" } if @plugins_to_be_installed.any?
+      run "spring stop"
+
+      @plugin_generators_to_run.each do |plugin_generator_name|
+        generate "#{plugin_generator_name} --skip_migrations=false"
+      end
+    end
+
     def run_migrations
       if @run_migrations
         say_status :running, "migrations"
@@ -221,5 +243,11 @@ def complete
         puts "Enjoy!"
       end
     end
+
+    private
+
+    def bundle_cleanly(&block)
+      Bundler.respond_to?(:with_unbundled_env) ? Bundler.with_unbundled_env(&block) : Bundler.with_clean_env(&block)
+    end
   end
 end