Remove use of `USE_DB` environment variable in code
Remove use of `USE_DB` environment variable in code

daiyu/gitlab-zh,dreampet/gitlab,iiet/iiet-git,axilleas/gitlabhq,screenpages/gitlabhq,dreampet/gitlab,darkrasid/gitlabhq,allysonbarros/gitlabhq,openwide-java/gitlabhq,htve/GitlabForChinese,shinexiao/gitlabhq,dreampet/gitlab,axilleas/gitlabhq,jirutka/gitlabhq,openwide-java/gitlabhq,allysonbarros/gitlabhq,allysonbarros/gitlabhq,screenpages/gitlabhq,stoplightio/gitlabhq,jirutka/gitlabhq,daiyu/gitlab-zh,openwide-java/gitlabhq,shinexiao/gitlabhq,iiet/iiet-git,screenpages/gitlabhq,icedwater/gitlabhq,htve/GitlabForChinese,icedwater/gitlabhq,t-zuehlsdorff/gitlabhq,dreampet/gitlab,darkrasid/gitlabhq,screenpages/gitlabhq,darkrasid/gitlabhq,iiet/iiet-git,t-zuehlsdorff/gitlabhq,LUMC/gitlabhq,axilleas/gitlabhq,axilleas/gitlabhq,stoplightio/gitlabhq,icedwater/gitlabhq,jirutka/gitlabhq,mmkassem/gitlabhq,htve/GitlabForChinese,mmkassem/gitlabhq,iiet/iiet-git,LUMC/gitlabhq,shinexiao/gitlabhq,jirutka/gitlabhq,htve/GitlabForChinese,openwide-java/gitlabhq,stoplightio/gitlabhq,daiyu/gitlab-zh,stoplightio/gitlabhq,allysonbarros/gitlabhq,LUMC/gitlabhq,shinexiao/gitlabhq,icedwater/gitlabhq,mmkassem/gitlabhq,dplarson/gitlabhq,LUMC/gitlabhq,daiyu/gitlab-zh,dplarson/gitlabhq,darkrasid/gitlabhq,mmkassem/gitlabhq,t-zuehlsdorff/gitlabhq,t-zuehlsdorff/gitlabhq,dplarson/gitlabhq,dplarson/gitlabhq