add a lot of software

android.md

@@ -1,10 +1,61 @@
 # Android Links
 
-This list contains nice open source software for Android.
+This is a collection of nice open source software for Android. Below,
+you find two categories. [Casual](#casual) contains software for
+everyone. [Nerdy](#nerdy) contains software which is suited for people
+who are technically more interested.
 
   - [Casual](#casual)
+      - [Communication](#communication)
+      - [File Synchronisation](#file-synchronisation)
+      - [Stores](#stores)
+      - [Video](#video)
   - [Nerdy](#nerdy)
+      - [Custom ROMs](#custom-roms)
+      - [System Tools](#system-tools)
+      - [Terminal](#terminal)
 
 ## Casual
 
+### Communication
+
+  - [**Riot**](https://about.riot.im/)  
+    Universal secure chat app entirely under your control, based on the
+    Matrix protocol
+
+### File Synchronisation
+
+  - [**Syncthing**](https://syncthing.net/)  
+    Synchronizes files between two or more computers in real time,
+    safely protected from prying eyes
+
+### Stores
+
+  - [**F-Droid**](https://f-droid.org/)  
+    F-Droid is an installable catalogue of FOSS applications
+
+### Video
+
+  - [**NewPipe**](https://newpipe.schabi.org/)  
+    Lightweight YouTube experience
+
 ## Nerdy
+
+### Custom ROMs
+
+  - [**LineageOS**](https://lineageos.org/)  
+    Operating system for various devices, based on the Android mobile
+    platform
+
+### System Tools
+
+  - [**ClassyShark3xodus**](https://forum.xda-developers.com/android/software-hacking/dexdump-xodus-trackers-apk-static-t3833391)  
+    Scan apps for trackers
+
+### Terminal
+
+  - [**Nix-on-Droid**](https://nix-on-droid.unboiled.info/)  
+    Nix package manager
+  - [**Termux**](https://termux.com/)  
+    Terminal emulator and Linux environment app that works directly with
+    no rooting or setup required