Fix #16 - background size
Fix #16 - background size

Add width/height to body and make sure background size is set to cover

sytac/nodeschool-signup,risdhillon/slack_demo,decloudscom/invite,outsideris/slack-invite-automation,m1103519/slack-invite-automation-fr,jonathanon/slackcommunityinvite,Kevin-Lee/slack-invite-automation,Doken-Tokuyama/slack-invite,outsideris/slack-invite-automation,ultias/globaltradingmarket,m1103519/slack-invite-automation-fr,decloudscom/invite,karma-platform/slackinvite,ultias/globaltradingmarket,risdhillon/slack_demo,jonathanon/slackcommunityinvite,Doken-Tokuyama/slack-invite,patrickdaniel/slack-invite-automation,Kevin-Lee/slack-invite-automation,outsideris/slack-invite-automation,sytac/nodeschool-signup,patrickdaniel/slack-invite-automation,dhaula/slack-auto-join,karma-platform/slackinvite,dhaula/slack-auto-join