make positions for channels and roles nicer (#1211)

* make role calculated position nicer

* make channels sortable in a nice way too

* stupid git web rebase editor

* Update Guild.js

* Update Guild.js

* Update Guild.js

* Update Guild.js

* Update RESTMethods.js

src/client/rest/RESTMethods.js

@@ -805,6 +805,15 @@ class RESTMethods {
     );
   }
 
+  setChannelPositions(guildID, channels) {
+    return this.rest.makeRequest('patch', Endpoints.Guild(guildID).channels, true, channels).then(() =>
+      this.client.actions.GuildChannelsPositionUpdate.handle({
+        guild_id: guildID,
+        channels,
+      }).guild
+    );
+  }
+
   addMessageReaction(message, emoji) {
     return this.rest.makeRequest(
       'put', Endpoints.Message(message).Reaction(emoji).User('@me'), true