docs: add detailed installation instructions for RPM and APT repositories to README

README.md

@@ -4,12 +4,67 @@ Convertis 0.3 is a modular Linux CLI for routing files through independently ins
 
 ## Installation
 
-Install the engine first:
+### Via repository
+
+Convertis is available on GNU/Linux for Debian-based systems and Fedora/CentOS-based systems via my Gitea repository.
+
+The repository contains the `convertis` engine and each official plugin as a separate package.
+
+#### RPM
+
+Add the RPM repository using the checked-in `.repo` file. This file configures both the package registry and the correct package-signing key.
+
+On RedHat distros:
+
+```sh
+sudo dnf config-manager --add-repo https://git.ewenlau.net/ewenlau/convertis/raw/branch/main/repo/gitea-ewenlau.repo
+```
+
+On Fedora 41+:
+
+```sh
+sudo dnf config-manager addrepo --from-repofile=https://git.ewenlau.net/ewenlau/convertis/raw/branch/main/repo/gitea-ewenlau.repo
+```
+
+On SUSE distros:
+
+```sh
+sudo zypper addrepo -f https://git.ewenlau.net/ewenlau/convertis/raw/branch/main/repo/gitea-ewenlau.repo
+```
+
+Then, install the package:
+
+On RedHat/Fedora:
+```sh
+sudo dnf install convertis
+```
+
+On SUSE distros:
+```sh
+sudo zypper install convertis
+```
+
+#### APT
+
+Add the repo:
+
+```sh
+sudo install -d -m 0755 /etc/apt/keyrings
+sudo curl https://git.ewenlau.net/api/packages/ewenlau/debian/repository.key -o /etc/apt/keyrings/gitea-ewenlau.asc
+echo "deb [signed-by=/etc/apt/keyrings/gitea-ewenlau.asc] https://git.ewenlau.net/api/packages/ewenlau/debian debian main" | sudo tee /etc/apt/sources.list.d/gitea-ewenlau.list
+sudo apt update
+```
+
+Then, install the package:
 
 ```sh
 sudo apt install convertis
-# or
-sudo dnf install convertis
+```
+
+If you want to install a specific version, append `=<version-number>-1`. For instance, to install version 0.3.0:
+
+```sh
+sudo apt install convertis=0.3.0-1
 ```
 
 Then install only the plugins you need. Each plugin is a separate package: