Optionally require 'active_record/railtie` in Rakefile

MSP-10905

Require in Rakefile so that db tasks are defined.  Make it optionally so
that `rake` doesn't error out when metasploit-framework installed with
`bundle install --without db`.

Author: limhoff-r7

Rakefile

@@ -1,4 +1,11 @@
 #!/usr/bin/env rake
 require File.expand_path('../config/application', __FILE__)
+require 'metasploit/framework/require'
+
+# @note must be before `Metasploit::Framework::Application.load_tasks`
+#
+# define db rake tasks from activerecord if activerecord is in the bundle.  activerecord could be not in the bundle if
+# the user installs with `bundle install --without db`
+Metasploit::Framework::Require.optionally_active_record_railtie
 
 Metasploit::Framework::Application.load_tasks