get user groups only when requested

lib/ood_support/user.rb

@@ -28,14 +28,9 @@ class User
 
     alias_method :id, :uid
 
-    # List of all groups that user belongs to
-    # @return [Array<String>] list of groups user is in
-    attr_reader :groups
-
     # @param user [Fixnum, #to_s] user id or name
     def initialize(user = Process.user)
       @passwd = user.is_a?(Fixnum) ? Etc.getpwuid(user) : Etc.getpwnam(user.to_s)
-      @groups = get_groups
     end
 
     # Determine whether user is part of specified group
@@ -51,6 +46,12 @@ def group
       groups.first
     end
 
+    # List of all groups that user belongs to
+    # @return [Array<String>] list of groups user is in
+    def groups
+      @groups ||= get_groups
+    end
+
     # The comparison operator for sorting values
     # @param other [User] user to compare against
     # @return [Fixnum] how users compare