Add contributing guide lines
Add contributing guide lines

Ghalko/waterbutler,TomBaxter/waterbutler,felliott/waterbutler,CenterForOpenScience/waterbutler,cosenal/waterbutler,hmoco/waterbutler,rafaeldelucena/waterbutler,rdhyee/waterbutler,kwierman/waterbutler,RCOSDP/waterbutler,Johnetordoff/waterbutler,icereval/waterbutler,chrisseto/waterbutler