readme - document using a custom assertion module
readme - document using a custom assertion module

#25
andywer/ava-ts,vdemedes/ava,Collinslenjo/ava,BarryThePenguin/ava,jrf0110/ava,sindresorhus/ava,andywer/ava-ts,avajs/ava,Collinslenjo/ava,joakimbeng/ava,matthewbauer/ava,uiureo/ava-power-assert,floatdrop/ava,avajs/ava,danielepolencic/ava