(doc): Upload uplinks documentation

wiki/README.md

@@ -6,8 +6,24 @@ It appeared that sinopia maintenance had stalled and the author had abandoned it
 so there was a suggestion that the sinopia-using community would benefit 
 from a fresh look at the code and the outstanding issues. So here we are 🎉🎉🎉.
 
-## Advanced Configurations
+## Getting Started
 
+<!---
+* [Command Line](cli.md)
+* [Understand the configuration file](config.md)
+-->
+* [Setting up *uplinks*](uplinks.md)
+<!---
+* [Packages Access](packages.md)
+* [Logs](logs.md)
+* [Configure the Web](web.md)
+* [Enable Notifications](notifications.md)
+* [Understand the storage](storage.md)
+* [Authorization and access](auth.md)
+* [Installing Plugins](plugins.md)
+-->
+
+## Advanced Configurations
 
 * [SSL Certificates](ssl.md)
 

wiki/uplinks.md

@@ -0,0 +1,31 @@
+# Uplinks
+
+An *upnlink* is a link with an external registry that provides acccess to external packages. 
+ 
+```yaml
+uplinks:
+  npmjs:
+   url: https://registry.npmjs.org/
+  server2:
+    url: http://mirror.local.net/
+    timeout: 100ms
+  server3:
+    url: http://mirror2.local.net:9000/
+  baduplink:
+    url: http://localhost:55666/
+```    
+### Configuration
+
+You can define mutiple uplinks and each of them must have an unique name (key). They can have two properties:
+
+Property | Type | Required | Example | Support | Description
+--- | --- | --- | --- | --- | ---
+url | string | Yes | https://registry.npmjs.org/ | all | The registry url
+timeout | string | No | 100ms | all | set new timeout
+cache | boolean | No |[true,false] | >= 2.1 | avoid cache tarballs
+
+### You Must know
+
+* Add uplinks might slow down the lookup of your packages.
+* Uplinks must be registries compatible with the `npm` endpoints. Eg: *verdaccio*, *sinopia@1.4.0*, *npmjs registry*, *yarn registry* and more.
+* Setting `cache` to false will help to save space in your hard drive.