Install some npm libraries as devDependencies

lib/install/coffee.rb

@@ -20,6 +20,6 @@
   "#{Webpacker.config.source_entry_path}/hello_coffee.coffee"
 
 say "Installing all Coffeescript dependencies"
-run "yarn add [email protected] coffee-loader"
+run "yarn add --dev [email protected] coffee-loader"
 
 say "Webpacker now supports Coffeeescript 🎉", :green

lib/install/elm.rb

@@ -21,8 +21,8 @@
   "#{Webpacker.config.source_path}/Main.elm"
 
 say "Installing all Elm dependencies"
-run "yarn add elm elm-webpack-loader"
-run "yarn add --dev elm-hot-loader"
+run "yarn add elm"
+run "yarn add --dev elm-hot-loader elm-webpack-loader"
 run "yarn run elm package install -- --yes"
 
 say "Updating webpack paths to include .elm file extension"

lib/install/erb.rb

@@ -20,6 +20,6 @@
   "#{Webpacker.config.source_entry_path}/hello_erb.js.erb"
 
 say "Installing all Erb dependencies"
-run "yarn add rails-erb-loader"
+run "yarn add --dev rails-erb-loader"
 
 say "Webpacker now supports Erb in JS 🎉", :green

lib/install/typescript.rb

@@ -41,6 +41,6 @@
   "#{Webpacker.config.source_entry_path}/hello_typescript.ts"
 
 say "Installing all typescript dependencies"
-run "yarn add typescript ts-loader #{additional_packages}"
+run "yarn add --dev typescript ts-loader #{additional_packages}"
 
 say "Webpacker now supports typescript 🎉", :green

lib/install/vue.rb

@@ -24,6 +24,7 @@
   "#{Webpacker.config.source_path}/app.vue"
 
 say "Installing all Vue dependencies"
-run "yarn add vue vue-loader vue-template-compiler"
+run "yarn add vue"
+run "yarn add --dev vue-loader vue-template-compiler"
 
 say "Webpacker now supports Vue.js 🎉", :green