Prevented usage of localhost siteUrl in production mode

Author: aileen

.gitignore

@@ -73,3 +73,6 @@ typings/
 public
 yarn-error.log
 .netlify/
+
+# Local Netlify folder
+.netlify

gatsby-config.js

@@ -22,6 +22,10 @@ try {
     }
 }
 
+if (process.env.NODE_ENV === `production` && config.siteUrl === `http://localhost:8000` && !process.env.SITEURL) {
+    throw new Error(`siteUrl can't be localhost and needs to be configured in siteConfig. Check the README.`) // eslint-disable-line
+}
+
 /**
 * This is the place where you can tell Gatsby which plugins to use
 * and set them up the way you want.

netlify.toml

@@ -1,5 +1,5 @@
 [build]
-  command = "gatsby build"
+  command = "NODE_ENV=production gatsby build"
   publish = "public/"
 
 [template]