allow sinopia plugins to install

lib/config.js

@@ -37,7 +37,7 @@ function Config(config) {
   self.localList = LocalData(
     Path.join(
       Path.resolve(Path.dirname(self.self_path || ''), self.storage),
-      '.verdaccio-db.json'
+      '.sinopia-db.json'
     )
   )
   if (!self.secret) {

lib/plugin-loader.js

@@ -21,6 +21,8 @@ function load_plugins(config, plugin_configs, params, sanity_check) {
     // npm package
     if (plugin === null && p.match(/^[^\.\/]/)) {
       plugin = try_load('verdaccio-' + p)
+      // compatibility for old sinopia plugins
+      plugin = try_load('sinopia-' + p)
     }
 
     if (plugin === null) {