add validation for configuration
add validation for configuration

artemutin/beets,ibmibmibm/beets,artemutin/beets,shamangeorge/beets,SusannaMaria/beets,beetbox/beets,sampsyo/beets,jcoady9/beets,beetbox/beets,Kraymer/beets,Kraymer/beets,xsteadfastx/beets,MyTunesFreeMusic/privacy-policy,madmouser1/beets,madmouser1/beets,madmouser1/beets,mosesfistos1/beetbox,jackwilsdon/beets,SusannaMaria/beets,madmouser1/beets,diego-plan9/beets,sampsyo/beets,SusannaMaria/beets,MyTunesFreeMusic/privacy-policy,xsteadfastx/beets,ibmibmibm/beets,jackwilsdon/beets,beetbox/beets,shamangeorge/beets,shamangeorge/beets,mosesfistos1/beetbox,xsteadfastx/beets,lengtche/beets,jcoady9/beets,ibmibmibm/beets,MyTunesFreeMusic/privacy-policy,sampsyo/beets,lengtche/beets,beetbox/beets,artemutin/beets,SusannaMaria/beets,diego-plan9/beets,lengtche/beets,Kraymer/beets,artemutin/beets,lengtche/beets,shamangeorge/beets,Kraymer/beets,jackwilsdon/beets,MyTunesFreeMusic/privacy-policy,jcoady9/beets,mosesfistos1/beetbox,pkess/beets,jcoady9/beets,ibmibmibm/beets,jackwilsdon/beets,mosesfistos1/beetbox,xsteadfastx/beets,pkess/beets,pkess/beets,sampsyo/beets,diego-plan9/beets,diego-plan9/beets,pkess/beets