Ruby script to deactivate or add users to database table
Some high level advice:


Fix your indendation.  For example, the indentation is randomly increased on this line: choice_client_ice = gets.chomp.to_i.  I mention this only because there is a lot of deep nesting here, which is confusing enough without incorrect indentation. Which brings me to...
Try to rewrite this entire thing, allowing yourself only 1 level of indentation (or 2, at most).  This will force you to separate high level logic and implementation detail, by pulling implementation out into its own functions.
Try to rewrite it, keeping your program logic and "views" separate.  All the puts statements are "view" code -- they are to your command line app what html files are to web apps.  Think about writing functions with names like main_menu_selection, which do nothing but present the user with his choices, get his selection, and return it.