Add production dependencies & build

node_modules/universal-user-agent/index.js

@@ -0,0 +1,15 @@
+module.exports = getUserAgentNode
+
+const osName = require('os-name')
+
+function getUserAgentNode () {
+  try {
+    return `Node.js/${process.version.substr(1)} (${osName()}; ${process.arch})`
+  } catch (error) {
+    if (/wmic os get Caption/.test(error.message)) {
+      return 'Windows <version undetectable>'
+    }
+
+    throw error
+  }
+}