add configuration class

app.rb

@@ -13,9 +13,14 @@ require "anyflake"
 
 require "jwt"
 
-SESSION_SECRET_HEX_LENGTH = 64
+$LOAD_PATH.unshift File.dirname(__FILE__) + "/lib"
 
-set :session_secret, ENV.fetch("SESSION_SECRET") { SecureRandom.hex(SESSION_SECRET_HEX_LENGTH) }
+require "config"
+
+SESSION_SECRET_HEX_LENGTH = 64
+JWT_SECRET_HEX_LENGTH = 64
+
+ENV_PREFIX = "KIPUNJI"
 
 CLK_TCK = 100
 PID_FILE_PATH = "/run/app/pid".freeze
@@ -38,7 +43,9 @@ DURATION_PARTS = [
   [1, "second", "s"]
 ].freeze
 
-JWT_SECRET = SecureRandom.bytes(64).freeze
+config = Config.new
+
+set :session_secret, config.session_secret.unwrap
 
 module Sinatra
   module RequestHeadersHelper