Update installation instructions for 4.3 on Ubuntu 24.04 and Debian 12 (

#1537)

* Update installation instructions...

...for Mastodon 4.3 on Ubuntu 24.04 and Debian 12.

* Reorder sections

To get rid of specifying a ruby version. Also simplifies the
steps even further.

* Allow other users to traverse mastodon home

instead of using group permissions. We heard a lot of
different opinions on this and it is clearly not a
solution for everyone, but in contrast to the group
permissions:

* `www-data` will not get write access to mastodon files
* this works identical on Debian and Ubuntu

content/en/admin/install.md

@@ -9,11 +9,13 @@ menu:
 
 ## Pre-requisites {#pre-requisites}
 
-* A machine running **Ubuntu 22.04** or **Debian 11** that you have root access to
+* A machine running **Ubuntu 24.04** or **Debian 12** that you have root access to
 * A **domain name** (or a subdomain) for the Mastodon server, e.g. `example.com`
 * An e-mail delivery service or other **SMTP server**
 
-You will be running the commands as root. If you aren’t already root, switch to root: `sudo su -`
+We will be using `example.com` as the domain in the following example. Please remember to replace it with your own domain before running any commands.
+
+You will be running the commands as root. If you aren’t already root, switch to root: `sudo -i`
 
 ### System repositories {#system-repositories}
 
@@ -52,52 +54,18 @@ apt install -y \
 
 #### Yarn {#yarn}
 
-```bash
-corepack enable
-yarn set version classic
-```
-
-### Installing Ruby {#installing-ruby}
-
-We will use rbenv to manage Ruby versions as it simplifies obtaining the correct versions and updating them when new releases are available. Since rbenv needs to be installed for an individual Linux user, we must first create the user account under which Mastodon will run:
-
-```bash
-adduser --disabled-login mastodon
-```
-
-We can then switch to the user:
-
-```bash
-su - mastodon
-```
-
-And proceed to install rbenv and rbenv-build:
-
-```bash
-git clone https://github.com/rbenv/rbenv.git ~/.rbenv
-echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
-echo 'eval "$(rbenv init -)"' >> ~/.bashrc
-exec bash
-git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build
-```
-
-Once this is done, we can install the correct Ruby version:
+Enable `corepack` so that the correct version of `yarn` can be installed automatically:
 
 ```bash
-RUBY_CONFIGURE_OPTS=--with-jemalloc rbenv install 3.2.3
-rbenv global 3.2.3
+corepack enable
 ```
 
-We’ll also need to install the bundler:
-
-```bash
-gem install bundler --no-document
-```
+### Creating the `mastodon` user {#creating-the-mastodon-user}
 
-Return to the root user:
+This is the user account under which Mastodon will run:
 
 ```bash
-exit
+adduser --disabled-password mastodon
 ```
 
 ## Setup {#setup}
@@ -106,7 +74,7 @@ exit
 
 #### Performance configuration (optional) {#performance-configuration-optional}
 
-For optimal performance, you may use [pgTune](https://pgtune.leopard.in.ua/#/) to generate an appropriate configuration and edit values in `/etc/postgresql/16/main/postgresql.conf` before restarting PostgreSQL with `systemctl restart postgresql`
+For optimal performance, you may use [pgTune](https://pgtune.leopard.in.ua/#/) to generate an appropriate configuration and edit values in `/etc/postgresql/16/main/postgresql.conf` before restarting PostgreSQL with `systemctl restart postgresql`.
 
 #### Creating a user {#creating-a-user}
 
@@ -144,6 +112,25 @@ git clone https://github.com/mastodon/mastodon.git live && cd live
 git checkout $(git tag -l | grep '^v[0-9.]*$' | sort -V | tail -n 1)
 ```
 
+#### Installing Ruby {#installing-ruby}
+
+We will use rbenv to manage Ruby versions as it simplifies obtaining the correct versions and updating them when new releases are available.
+Install rbenv and ruby-build:
+
+```bash
+git clone https://github.com/rbenv/rbenv.git ~/.rbenv
+echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
+echo 'eval "$(rbenv init -)"' >> ~/.bashrc
+exec bash
+git clone https://github.com/rbenv/ruby-build.git "$(rbenv root)"/plugins/ruby-build
+```
+
+Once this is done, we can install the correct Ruby version:
+
+```bash
+RUBY_CONFIGURE_OPTS=--with-jemalloc rbenv install
+```
+
 #### Installing the last dependencies {#installing-the-last-dependencies}
 
 Now to install Ruby and JavaScript dependencies:
@@ -152,7 +139,7 @@ Now to install Ruby and JavaScript dependencies:
 bundle config deployment 'true'
 bundle config without 'development test'
 bundle install -j$(getconf _NPROCESSORS_ONLN)
-yarn install --pure-lockfile
+yarn install
 ```
 
 {{< hint style="info" >}}
@@ -164,7 +151,7 @@ The two `bundle config` commands are only needed the first time you're installin
 Run the interactive setup wizard:
 
 ```bash
-RAILS_ENV=production bundle exec rake mastodon:setup
+RAILS_ENV=production bin/rails mastodon:setup
 ```
 
 This will:
@@ -204,21 +191,25 @@ rm /etc/nginx/sites-enabled/default
 Then edit `/etc/nginx/sites-available/mastodon` to 
 
 1. Replace `example.com` with your own domain name
-2. Uncomment the `ssl_certificate` and `ssl_certificate_key` lines and replace the two lines with (ignore this step if you are bringing your own certificate)
+2. Uncomment the `ssl_certificate` and `ssl_certificate_key` (ignore this step if you are bringing your own certificate):
 
-```
-ssl_certificate     /etc/ssl/certs/ssl-cert-snakeoil.pem;
-ssl_certificate_key /etc/ssl/private/ssl-cert-snakeoil.key;
-```
+    ```
+    ssl_certificate     /etc/letsencrypt/live/example.com/fullchain.pem;
+    ssl_certificate_key /etc/letsencrypt/live/example.com/privkey.pem;;
+    ```
 
 3. Make any other adjustments you might need.
 
-Un-comment the lines starting with `ssl_certificate` and `ssl_certificate_key`, updating the path with the correct domain name.
+Allow other users to traverse the mastodon user's home directory, so that nginx's `www-data` user can access asset files:
+
+```bash
+chmod o+x /home/mastodon
+```
 
-Reload nginx for the changes to take effect:
+Restart nginx for the changes to take effect:
 
 ```bash
-systemctl reload nginx
+systemctl restart nginx
 ```
 
 At this point, you should be able to visit your domain in the browser and see the elephant hitting the computer screen error page. This is because we haven’t started the Mastodon process yet.