Minor corrections and clarification for Alpine standard v.3.10

docs/installation/alpine_linux_en.md

@@ -1,7 +1,9 @@
 # Installing on Alpine Linux
 ## Installation
 
-This guide is a step-by-step installation guide for Alpine Linux. It also assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.linode.com/docs/tools-reference/custom-kernels-distros/install-alpine-linux-on-your-linode/#configuration). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su -l <username> -s $SHELL -c 'command'` instead.
+This guide is a step-by-step installation guide for Alpine Linux. The instructions were verified against Alpine v.3.10 standard image. You might miss additional dependencies if you use `netboot` instead.
+
+It assumes that you have administrative rights, either as root or a user with [sudo permissions](https://www.linode.com/docs/tools-reference/custom-kernels-distros/install-alpine-linux-on-your-linode/#configuration). If you want to run this guide with root, ignore the `sudo` at the beginning of the lines, unless it calls a user like `sudo -Hu pleroma`; in this case, use `su -l <username> -s $SHELL -c 'command'` instead.
 
 ### Required packages
 
@@ -20,12 +22,13 @@ This guide is a step-by-step installation guide for Alpine Linux. It also assume
 
 ### Prepare the system
 
-* First make sure to have the community repository enabled:
+* The community repository must be enabled in `/etc/apk/repositories`. Depending on which version and mirror you use this looks like `http://alpine.42.fr/v3.10/community`. If you autogenerated the mirror during installation:
 
 ```shell
-echo "https://nl.alpinelinux.org/alpine/latest-stable/community" | sudo tee -a /etc/apk/repository
+awk 'NR==2' /etc/apk/repositories | sed 's/main/community/' | tee -a /etc/apk/repositories
 ```
 
+
 * Then update the system, if not already done:
 
 ```shell
@@ -77,7 +80,8 @@ sudo rc-update add postgresql
 * Add a new system user for the Pleroma service:
 
 ```shell
-sudo adduser -S -s /bin/false -h /opt/pleroma -H pleroma
+sudo addgroup pleroma
+sudo adduser -S -s /bin/false -h /opt/pleroma -H -G pleroma pleroma
 ```
 
 **Note**: To execute a single command as the Pleroma system user, use `sudo -Hu pleroma command`. You can also switch to a shell by using `sudo -Hu pleroma $SHELL`. If you don’t have and want `sudo` on your system, you can use `su` as root user (UID 0) for a single command by using `su -l pleroma -s $SHELL -c 'command'` and `su -l pleroma -s $SHELL` for starting a shell.
@@ -164,7 +168,26 @@ If that doesn’t work, make sure, that nginx is not already running. If it stil
 sudo cp /opt/pleroma/installation/pleroma.nginx /etc/nginx/conf.d/pleroma.conf
 ```
 
-* Before starting nginx edit the configuration and change it to your needs (e.g. change servername, change cert paths)
+* Before starting nginx edit the configuration and change it to your needs. You must change change `server_name` and the paths to the certificates. You can use `nano` (install with `apk add nano` if missing).
+
+```
+server {
+    server_name    your.domain;
+    listen         80;
+    ...
+}
+
+server {
+    server_name your.domain;
+    listen 443 ssl http2;
+    ...
+    ssl_trusted_certificate   /etc/letsencrypt/live/your.domain/chain.pem;
+    ssl_certificate           /etc/letsencrypt/live/your.domain/fullchain.pem;
+    ssl_certificate_key       /etc/letsencrypt/live/your.domain/privkey.pem;
+    ...
+}
+```
+
 * Enable and start nginx:
 
 ```shell