Use guard-webpacker to start webpacker server

Gemfile

@@ -63,6 +63,7 @@ group :development do
   gem 'better_errors'
   gem 'binding_of_caller'
   gem 'guard-livereload', '~> 2.5', require: false
+  gem 'guard-webpacker', '~> 0.2.1'
   # Access an interactive console on exception pages or by calling 'console'
   # anywhere in the code.
   gem 'web-console', '>= 4.1.0'

Gemfile.lock

@@ -138,6 +138,9 @@ GEM
       guard (~> 2.1)
       guard-compat (~> 1.1)
       rspec (>= 2.99.0, < 4.0)
+    guard-webpacker (0.2.1)
+      guard (>= 2)
+      guard-compat (~> 1.0)
     http_parser.rb (0.6.0)
     i18n (1.8.10)
       concurrent-ruby (~> 1.0)
@@ -352,6 +355,7 @@ DEPENDENCIES
   guard-livereload (~> 2.5)
   guard-rails (~> 0.8.1)
   guard-rspec (~> 4.7.3)
+  guard-webpacker (~> 0.2.1)
   kaminari (~> 1.2)
   listen (~> 3.3)
   pg (~> 1.2.3)

Guardfile

@@ -85,6 +85,17 @@ group :frontend do
     watch('Gemfile.lock')
     watch(%r{^(config|lib)/.*})
   end
+
+  ### Guard::Webpacker
+  #  available options:
+  #  - :bin (defaults to "webpack-dev-server") to run
+  #  - :watch (defaults to "default") can be an array
+  #  - :colors (defaults to 1)
+  #  - :progress
+  guard :webpacker do
+    watch('config/webpacker.yml')
+    watch(%r{^config/webpacker/(.+)$})
+  end
 end
 
 group :backend do

config/webpacker.yml

@@ -23,7 +23,7 @@ development:
   dev_server:
     https: false
     host: localhost
-    port: 3035
+    port: 3037
     # Hot Module Replacement updates modules while the application is running without a full reload
     hmr: false
     client: