fix(registry): be better at using the correct registry (relevant for npme)

Closes #53

src/lib/get-registry.js

@@ -0,0 +1,12 @@
+module.exports = function (pkg, conf) {
+  if (pkg.publishConfig && pkg.publishConfig.registry) return pkg.publishConfig.registry
+
+  if (pkg.name[0] !== '@') return conf.get('registry') || 'https://registry.npmjs.org/'
+
+  const scope = pkg.name.split('/')[0]
+  const scopedRegistry = conf.get(`${scope}/registry`)
+
+  if (scopedRegistry) return scopedRegistry
+
+  return conf.get('registry') || 'https://registry.npmjs.org/'
+}