Added test instructions to HACKING.md
Added test instructions to HACKING.md

pwplus/securedrop,harlo/securedrop,ageis/securedrop,micahflee/securedrop,ehartsuyker/securedrop,heartsucker/securedrop,jeann2013/securedrop,jeann2013/securedrop,kelcecil/securedrop,jeann2013/securedrop,chadmiller/securedrop,pwplus/securedrop,conorsch/securedrop,garrettr/securedrop,harlo/securedrop,kelcecil/securedrop,jrosco/securedrop,GabeIsman/securedrop,garrettr/securedrop,heartsucker/securedrop,micahflee/securedrop,pwplus/securedrop,GabeIsman/securedrop,pwplus/securedrop,jeann2013/securedrop,heartsucker/securedrop,ehartsuyker/securedrop,ageis/securedrop,GabeIsman/securedrop,conorsch/securedrop,chadmiller/securedrop,GabeIsman/securedrop,harlo/securedrop,conorsch/securedrop,jrosco/securedrop,chadmiller/securedrop,garrettr/securedrop,GabeIsman/securedrop,garrettr/securedrop,ageis/securedrop,jaseg/securedrop,ehartsuyker/securedrop,chadmiller/securedrop,harlo/securedrop,pwplus/securedrop,ageis/securedrop,jaseg/securedrop,micahflee/securedrop,jeann2013/securedrop,conorsch/securedrop,ehartsuyker/securedrop,kelcecil/securedrop,kelcecil/securedrop,jaseg/securedrop,jrosco/securedrop,kelcecil/securedrop,jaseg/securedrop,heartsucker/securedrop,kelcecil/securedrop,GabeIsman/securedrop,harlo/securedrop,jeann2013/securedrop,harlo/securedrop,chadmiller/securedrop,jrosco/securedrop,chadmiller/securedrop,jaseg/securedrop,pwplus/securedrop,conorsch/securedrop,ehartsuyker/securedrop,ehartsuyker/securedrop,heartsucker/securedrop,jrosco/securedrop,micahflee/securedrop,jaseg/securedrop,jrosco/securedrop