Fix docker instruction formating in README
Fix docker instruction formating in README

puppet-community/puppetboard,johnzimm/puppetboard,mterzo/puppetboard,puppet-community/puppetboard,mterzo/puppetboard,johnzimm/puppetboard,grandich/puppetboard,grandich/puppetboard,grandich/puppetboard,mterzo/puppetboard,johnzimm/xx-puppetboard,voxpupuli/puppetboard,johnzimm/xx-puppetboard,johnzimm/puppetboard,voxpupuli/puppetboard,mterzo/puppetboard,johnzimm/xx-puppetboard,puppet-community/puppetboard,johnzimm/xx-puppetboard,voxpupuli/puppetboard,grandich/puppetboard