cleanup and update README

README.md

@@ -1,13 +1,25 @@
+Build Archlinux packages in rootless podman container
 
+### Why
 
-Command to build
+1. `sudo` is run inside container (required for makepkg). Does not affect host system
+2. Does not install unnecessary make dependencies in host system
+3. Build runs in clean environment. 
+
+### Usage
+
+1. Remove/Replace mirror url. I run [pacoloco](https://github.com/anatol/pacoloco) locally at archmirror.i.balki.me
+2. Change PACKAGER setting to your name/email
+3. Add AUR dependencies in a folder `deps/` (if any)
+
+### Command to build
 
 ```
 cd ~/projects/mine/aur_builder/
 podman build -t gitea.balki.me/balki/aur_builder:exp .
 ```
 
-Command to run
+### Command to run
 
 ```
 cd /home/balki/gotosocial_aur/