manual.adoc in decidim-0.28.3

- old
+ new

@@ -25,10 +25,10 @@
 First, we are going to install https://github.com/rbenv/rbenv[rbenv], for managing various ruby versions. You could also use https://rvm.io/[rvm] or https://github.com/asdf-vm/asdf[asdf] as alternatives on this step.
 
 [source,bash]
 ----
 sudo apt update
-sudo apt install -y build-essential curl git libssl-dev zlib1g-dev
+sudo apt install -y build-essential curl git libssl-dev zlib1g-dev p7zip
 git clone https://github.com/rbenv/rbenv.git ~/.rbenv
 echo 'export PATH="$HOME/.rbenv/bin:$PATH"' >> ~/.bashrc
 echo 'eval "$(rbenv init -)"' >> ~/.bashrc
 source ~/.bashrc
 git clone https://github.com/rbenv/ruby-build.git ~/.rbenv/plugins/ruby-build