Add rails runner troubleshooting guide

doc/administration/operations/rails_console.md

@@ -148,3 +148,23 @@ Traceback (most recent call last):
       [traceback removed]
 /opt/gitlab/..../runner_command.rb:42:in `load': cannot load such file -- /tmp/helloworld.rb (LoadError)
 ```
+
+In case you encouter a similar error to this:
+
+```plaintext
+[root ~]# sudo gitlab-rails runner helloworld.rb 
+Please specify a valid ruby command or the path of a script to run.
+Run 'rails runner -h' for help.
+
+undefined local variable or method `helloworld' for main:Object
+```
+
+You can either move the file to the `/tmp` directory or create a new directory onwed by the user `git` and save the script in that directory as illustrated below:
+
+```shell
+sudo mkdir /scripts
+sudo mv /script_path/helloworld.rb /scripts
+sudo chown -R git:git /scripts
+sudo chmod 700 /scripts
+sudo gitlab-rails runner /scripts/helloworld.rb
+```