Update README-ec2.md
Update README-ec2.md

ssadedin/seqr,macarthur-lab/xbrowse,ssadedin/seqr,macarthur-lab/xbrowse,macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr,ssadedin/seqr,macarthur-lab/seqr,macarthur-lab/seqr,macarthur-lab/seqr,macarthur-lab/seqr,macarthur-lab/seqr,macarthur-lab/xbrowse,macarthur-lab/xbrowse,ssadedin/seqr