v2.0.0

• Breaking change: user is now github_user to better inherent from sinatra_auth_github
• Comprehensive tests
• Improved documentation
• Stricter dependency requirements
• Sets WARDEN_GITHUB_VERIFIER_SECRET to better protect sessions
• Fix for locals not being properly passed to default template
• Fix for default template not displaying redirect URL
• Fix for default template not properly halting execution for invalid users