Add Ruby version to Gemfile

Since Bundler 2.4.19, including in Ruby 3.2.3, it's possible to define
the Ruby version in the Gemfile by indicating which file contains the
version [1].

There are at least two practical cases where this is an advantage.

First, people using RVM in development will no longer accidentally run
the application using the wrong Ruby version (which, before these
changes, might happen if they switch to a branch using a different Ruby
version and forget to run `rvm use` or exit the current folder and enter
it again) because they will get an error when trying to do so.

Second, people using services like Heroku no longer need to modify the
Gemfile.

The disadvantage is that, now, every time we update the Ruby version, we
have to remember to run `bundle` so our `Gemfile.lock` gets the new
version.

[1] https://github.com/rubygems/rubygems/releases/tag/bundler-v2.4.19

Dockerfile

@@ -46,6 +46,7 @@ RUN curl -sL https://github.com/nodenv/node-build/archive/master.tar.gz | tar xz
 
 # Use the Gemfiles as Docker cache markers. Always bundle before copying app src.
 # (the src likely changed and we don't want to invalidate Docker's cache too early)
+COPY .ruby-version ./
 COPY Gemfile* ./
 RUN bundle install
 

Gemfile

@@ -1,5 +1,7 @@
 source "https://rubygems.org"
 
+ruby file: ".ruby-version"
+
 gem "rails", "7.0.8.7"
 
 gem "acts-as-taggable-on", "~> 11.0.0"

Gemfile.lock

@@ -804,5 +804,8 @@ DEPENDENCIES
   wicked_pdf (~> 2.8.1)
   wkhtmltopdf-binary (~> 0.12.6)
 
+RUBY VERSION
+   ruby 3.2.5p208
+
 BUNDLED WITH
    2.4.19

docs/en/installation/deploying-on-heroku.md

@@ -58,7 +58,7 @@ This tutorial assumes that you have already managed to clone Consul Democracy on
 
   **Remember not to commit the file if you have any sensitive information in it!**
 
-6. To ensure Heroku correctly detects and uses the node.js and ruby versions defined in the project, we need to make the following changes:
+6. To ensure Heroku correctly detects and uses the node.js version defined in the project, we need to make the following changes:
 
   In package.json, add the node.js version:
 
@@ -74,18 +74,6 @@ This tutorial assumes that you have already managed to clone Consul Democracy on
   heroku buildpacks:add heroku/nodejs
   ```
 
-  In _Gemfile_, add the ruby version and run bundle:
-
-  ```Gemfile
-  ruby file: ".ruby-version"
-  ```
-
-  and apply:
-
-  ```bash
-  heroku buildpacks:set heroku/ruby
-  ```
-
 7. You can now push your app using:
 
   ```bash

docs/es/installation/deploying-on-heroku.md

@@ -58,7 +58,7 @@ Este tutorial asume que ya has conseguido clonar Consul Democracy en tu máquina
 
   **¡Recuerda no añadir el archivo si tienes información sensible en él!**
 
-6. Para que Heroku detecte y utilice correctamente las versiones de node.js y ruby definidas en el proyecto deberemos añadir los siguientes cambios:
+6. Para que Heroku detecte y utilice correctamente la versión de node.js definida en el proyecto deberemos añadir los siguientes cambios:
 
   En el _package.json_  añadir la versión de node.js:
 
@@ -74,18 +74,6 @@ Este tutorial asume que ya has conseguido clonar Consul Democracy en tu máquina
   heroku buildpacks:add heroku/nodejs
   ```
 
-  En el _Gemfile_ añadir la versión de ruby y ejecutar bundle:
-
-  ```Gemfile
-  ruby file: ".ruby-version"
-  ```
-
-  y aplicar:
-
-  ```bash
-  heroku buildpacks:set heroku/ruby
-  ```
-
 7. Ahora ya puedes subir tu aplicación utilizando:
 
   ```bash