Minor details added to subheadings

Indexers.md

@@ -1,12 +1,25 @@
 # Usenet
 ## Newznab
+
+Configure your own NZB indexer or use an aggregator like [NZBHydra](https://github.com/theotherp/nzbhydra2).
 ## Omgwtfnzbs
 
 # Torrent
 ## Gazelle API
 ## IP Torrents
+
+Private tracker
+
 ## Nyaa
 ## Rarbg
+
+Public tracker
+
 ## Torrent RSS Feed
 ## TorrentLeech
-# Torznab
+
+Private tracker that requires an application. 
+
+## Torznab
+
+Used with a tool such as [Jackett](https://github.com/Jackett/Jackett) to add other trackers.