Update attribution in Gemspec

Author: benbalter

jekyll-theme-midnight.gemspec

@@ -3,10 +3,10 @@
 Gem::Specification.new do |s|
   s.name          = "jekyll-theme-midnight"
   s.version       = "0.0.1"
-  s.authors       = ["Please come forward"]
+  s.authors       = ["Matt Graham", "GitHub, Inc."]
   s.email         = ["opensource+jekyll-theme-midnight@github.com"]
   s.homepage      = "https://github.com/pages-themes/midnight"
-  s.summary       = "Midnight is a theme for GitHub Pages"
+  s.summary       = "Midnight is a Jekyll theme for GitHub Pages"
 
   s.files         = `git ls-files -z`.split("\x0").select do |f|
     f.match(%r{^((_includes|_layouts|_sass|assets)/|(LICENSE|README)((\.(txt|md|markdown)|$)))}i)