Make dev server binstub optional (#1024)

Author: gauravtiwari

lib/tasks/webpacker/check_binstubs.rake

@@ -1,7 +1,7 @@
 namespace :webpacker do
   desc "Verifies that webpack & webpack-dev-server are present."
   task :check_binstubs do
-    unless Bundler.which("webpack") && Bundler.which("webpack-dev-server")
+    unless Bundler.which("webpack")
       $stderr.puts "webpack binstubs not found.\n"\
            "Have you run rails webpacker:install ?\n"\
            "Make sure the bin directory or binstubs are not included in .gitignore\n"\

lib/webpacker/compiler.rb

@@ -53,7 +53,7 @@ def record_compilation_digest
     def run_webpack
       logger.info "Compiling…"
 
-      sterr, stdout, status = Open3.capture3(webpack_env, "#{RbConfig.ruby} ./bin/webpack")
+      sterr, stdout, status = Open3.capture3(webpack_env, "bundle exec webpack")
 
       if status.success?
         logger.info "Compiled all packs in #{config.public_output_path}"