Add license information to gemspec

Author: Ben Lavender

chatops-controller.gemspec

@@ -7,10 +7,10 @@ require "chatops/controller/version"
 Gem::Specification.new do |s|
   s.name        = "chatops-controller"
   s.version     = ChatopsController::VERSION
-  s.authors     = ["Ben Lavender"]
+  s.authors     = ["Ben Lavender", "GitHub"]
   s.homepage    = "https://github.com/github/chatops-controller"
   s.email       = ["opensource+chatops-controller@github.com"]
-  s.license     = "unknown - maybe we'll open source this?"
+  s.license     = "MIT"
   s.summary     = %q{Rails helpers to create JSON-RPC chatops}
   s.description = %q{See the README for documentation"}