Reverse dependencies for rack-handlers

Latest version of the following gems require rack-handlers

Gem	Version	Date	Downloads
openbel-api +53.8 Thousand Downloads	`1.2.12` May 22, 2017	May 22, 2017	53.8 Thousand
rest-gw2 +10.1 Thousand Downloads	`0.5.0` December 26, 2018	December 26, 2018	10.1 Thousand
saya +4.31 Thousand Downloads	`0.0.1` July 12, 2013	July 12, 2013	4.31 Thousand
statusboard +3.8 Thousand Downloads	`0.1.0` May 25, 2014	May 25, 2014	3.8 Thousand