implement adding users

lib/user.rb

@@ -1,8 +1,37 @@
 
 module User
+  require 'system'
 
   def self.install(context)
     puts "Creating #{context.type}: #{context.user_name}"
+    System.install(["zsh"])
+
+    user_exists = system("getent passwd #{context.user_name} > /dev/null")
+    
+    group = case context.type
+      when :user
+      "users"
+      when :service
+      "services"
+      else
+      rise "Can not create user for unknow type: #{context.type}"
+      end
+
+
+    group_exists = system("getent group #{group} > /dev/null")
+    unless group_exists
+      puts "Group '#{group}' does not exist. Creating it..."
+      system("sudo groupadd #{group}")
+    end
+
+    if user_exists
+      puts "User #{context.user_name} already exists. Updating shell and adding to group '#{group}'."
+      system("sudo usermod -s /usr/bin/zsh #{context.user_name}")
+      system("sudo usermod -g #{group} #{context.user_name}")
+    else
+      puts "User #{context.user_name} does not exist. Creating user..."
+      system("sudo adduser --disabled-login --gecos \"\" --ingroup #{group} --shell /usr/bin/zsh #{context.user_name}")
+    end
   end
 
 end