Merge pull request #113 from watilde/feature/safe-upgrade

Added version to datadir to store the version of the how-to-npm package.

Author: watilde

index.js

@@ -21,6 +21,7 @@ var shop = module.exports = adventure({
     bg: 'white',
     fg: 'red'
   },
+  version: require('./package.json').version,
   commands: [{
     name: 'reset-registry',
     handler: function (workshopper) {
@@ -64,6 +65,13 @@ function cpclean (item) {
     rimraf.sync(to)
     cpr(from, to)
   }
+
+  try {
+    var versionStat = fs.readFileSync(shop.datadir + '/version', 'utf8')
+    if (versionStat !== shop.options.version) throw Error('eold')
+  } catch (e) {
+    fs.writeFileSync(shop.datadir + '/version', shop.options.version)
+  }
 }
 
 cpclean('registry')