Namespacing directory generation fix

lib/generators/rails/templates/index.json.jbuilder

@@ -1 +1 @@
-json.array! @<%= plural_table_name %>, partial: "<%= plural_table_name %>/<%= singular_table_name %>", as: :<%= singular_table_name %>
+json.array! @<%= plural_table_name %>, partial: '<%= plural_table_name.gsub('_', '/') %>/<%= singular_table_name %>', as: :<%= singular_table_name %>

lib/generators/rails/templates/show.json.jbuilder

@@ -1 +1 @@
-json.partial! "<%= plural_table_name %>/<%= singular_table_name %>", <%= singular_table_name %>: @<%= singular_table_name %>
+json.partial! "<%= plural_table_name.gsub('_', '/') %>/<%= singular_table_name %>", <%= singular_table_name %>: @<%= singular_table_name %>

test/jbuilder_generator_with_namespace_test.rb

@@ -0,0 +1,36 @@
+require 'test_helper'
+require 'rails/generators/test_case'
+require 'generators/rails/jbuilder_generator'
+
+class JbuilderGeneratorWithNamespaceTest < Rails::Generators::TestCase
+  tests Rails::Generators::JbuilderGenerator
+  arguments %w(api/foo bar:integer baz:string)
+  destination File.expand_path('../tmp', __FILE__)
+  setup :prepare_destination
+
+  test 'all views are generated' do
+    run_generator
+
+    %w(index show).each do |view|
+      assert_file "app/views/api/foos/#{view}.json.jbuilder"
+    end
+    assert_file "app/views/api/foos/_api_foo.json.jbuilder"
+  end
+
+  test 'the files are correctly structured to work' do
+    run_generator
+
+    assert_file 'app/views/api/foos/index.json.jbuilder' do |content|
+      assert_match %r{json.array! @api_foos, partial: 'api/foos/api_foo', as: :api_foo}, content
+    end
+
+    assert_file 'app/views/api/foos/show.json.jbuilder' do |content|
+      assert_match %r{json.partial! \"api/foos/api_foo\", api_foo: @api_foo}, content
+    end
+
+    assert_file 'app/views/api/foos/_api_foo.json.jbuilder' do |content|            
+      assert_match %r{json\.extract! api_foo, :id, :bar, :baz, :created_at, :updated_at}, content
+      assert_match %r{json\.url api_foo_url\(api_foo, format: :json\)}, content
+    end
+  end
+end