Fix warning in 5.0.gemfile

Author: andrew

Appraisals

@@ -4,5 +4,5 @@ end
 
 appraise "5.0" do
   gem "rails", "~> 5.0"
-  gem "sinatra", github: "sinatra/sinatra"
+  gem "sinatra", git: "https://github.com/sinatra/sinatra"
 end

gemfiles/5.0.gemfile

@@ -5,6 +5,6 @@ source "https://rubygems.org"
 gem "appraisal"
 gem "codeclimate-test-reporter"
 gem "rails", "~> 5.0"
-gem "sinatra", :github => "sinatra/sinatra"
+gem "sinatra", :git => "https://github.com/sinatra/sinatra"
 
 gemspec :path => "../"