Added info to README on how to join the Commitmas Slack page
Merge pull request #1 from joshcoen/master

Added info to README on how to join the Commitmas Slack page
Merge pull request #2 from bdwill/master

Suggestions for changes to Commitmas
changed the slack URL to include the team name
Merge pull request #4 from joshcoen/master

changed the slack URL to include the team name
Added some details to Advanced