move db test task clearing above any rake invocation
move db test task clearing above any rake invocation

generalize rake task clearing method name

jonseaberg/heroku-buildpack-turbo-sprockets,pilotcreative/heroku-buildpack-ruby,makifund/heroku-buildpack-ruby,jonseaberg/heroku-buildpack-turbo-sprockets,pilotcreative/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,Scalingo/ruby-buildpack,ericboehs/heroku-buildpack-ruby,pkgr/heroku-buildpack-ruby,ericboehs/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,zunda/heroku-buildpack-ruby,mattmanning/heroku-buildpack-ruby-jekyll,brightbytes/heroku-buildpack-ruby-without-assets-precompile,andycroll/heroku-buildpack-jekyll,ruby/heroku-buildpack-www-ruby-lang,andycroll/heroku-buildpack-jekyll,heroku/heroku-buildpack-ruby,Genius/heroku-buildpack-ruby,pkgr/heroku-buildpack-ruby,Genius/heroku-buildpack-ruby,makifund/heroku-buildpack-ruby,zunda/heroku-buildpack-ruby,instacart/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,donnykurnia/heroku-buildpack-ruby,orenyk/heroku-buildpack-ruby,Scalingo/ruby-buildpack,brightbytes/heroku-buildpack-ruby-without-assets-precompile,heroku/heroku-buildpack-ruby,mattmanning/heroku-buildpack-ruby-jekyll