How to install ruby ​​and rails as a normal user?

Question

Debian

I install the Redmine 3 system on Debian 9 ERP
Everything is installed as a root user without problems, but it confuses what works from root
I tried to go the other way:
According to the instructions - redmine-git-hosting.io/how-to/install-redmine we create user adduser --disabled-password redmineafter which we install all packages from him, but what if curl -sSL https://get.rvm.io | bash -s stableroot rights are required already at step 3
An error pops up:

Running 'apt-get --quiet --yes update' would require sudo, but 'sudo' is not found!

sudo is not in the system, installed, requires the password of the redmine user in which there is no password, even if setting the password does not work (I also tried the password from the root user)

Answer 1

Here .