Display variable content, not variable name in Ruby on Rails

The Liquid template engine was created just for this kind of use case. You could have the backend user include a special string in double curly braces such as {{name}} that you then populate at render time. For example, the backend user would set the welcome message to "Welcome to {{name}}, our latest member." which would be stored in your database. Assuming that the current_user variable represents the user that's currently logged in, you could render the customized message with the following code:

template = Liquid::Template.parse(messages.welcomeMessage) 
template.render('name' => current_user.name)              

Another, more dangerous strategy is to use eval which will interpret the string as code:

puts eval("\"" + messages.welcomeMessage + "\"")

This isn't recommended because it could allow a malicious user to run arbitrary code. By using Liquid, you maintain control of the exact value that gets used in place of {{name}}.

Try this:

Welcome to <%= userInfo["name"] %>, our latest member