Finish documentation for now

app/models/session.rb

@@ -1,10 +1,32 @@
+# A Session contains the information about a logged-in user.
 class Session < ApplicationRecord
+  # @!attribute ip
+  #   @return [String]
+  #     the IP address of the client that started the session.
+  #
+  # @!attribute expires
+  #   @return [TimeWithZone]
+  #     when the user must be logged out.
+  #
+  # @!attribute remember_digest
+  #   @return [String]
+  #     a salted hash of the user's remember token. This token may be used if
+  #     the user continues a session by using the 'remember me' option.
+  #
+  # @!attribute active
+  #   @return [Boolean]
+  #     whether or not the session may still be used to authenticate.
+  #     Inactive sessions may be retained for logging, but must not allow a user
+  #     to continue using the system.
+
   belongs_to :user
 
+  # @return [String] a new random token.
   def Session.new_token
     SecureRandom.urlsafe_base64
   end
 
+  # @return [String] a BCrypt digest of the given string.
   def Session.digest(string)
     cost = ActiveModel::SecurePassword.min_cost ? BCrypt::Engine::MIN_COST :
                                                   BCrypt::Engine.cost