Require Rails frameworks before using

Jbuilder since #501 depends on Action View so we need to make it a
dependency.

Also we should be requiring both action_view and active_support before
using it.

Closes #518.

jbuilder.gemspec

@@ -10,6 +10,7 @@ Gem::Specification.new do |s|
   s.required_ruby_version = '>= 2.2.2'
 
   s.add_dependency 'activesupport', '>= 5.0.0'
+  s.add_dependency 'actionview', '>= 5.0.0'
 
   if RUBY_ENGINE == 'rbx'
     s.add_development_dependency('racc')

lib/jbuilder.rb

@@ -1,3 +1,4 @@
+require 'active_support'
 require 'jbuilder/jbuilder'
 require 'jbuilder/blank'
 require 'jbuilder/key_formatter'

lib/jbuilder/collection_renderer.rb

@@ -1,5 +1,6 @@
 require 'delegate'
 require 'active_support/concern'
+require 'action_view'
 
 begin
   require 'action_view/renderer/collection_renderer'

lib/jbuilder/railtie.rb

@@ -1,4 +1,4 @@
-require 'rails/railtie'
+require 'rails'
 require 'jbuilder/jbuilder_template'
 
 class Jbuilder

test/test_helper.rb

@@ -1,14 +1,11 @@
 require "bundler/setup"
 
-require "active_support"
+require "jbuilder"
+
 require "active_support/core_ext/array/access"
 require "active_support/cache/memory_store"
 require "active_support/json"
 require "active_model"
-require "action_view"
-require "rails/version"
-
-require "jbuilder"
 
 require "active_support/testing/autorun"
 require "mocha/minitest"