Added changelog.
Added changelog.

timotius02/reactfire,StevenLangbroek/reactfire,ronlobo/reactfire,FirebaseExtended/reactfire,ramyathulasingam/reactfire,Shraymonks/reactfire,FirebaseExtended/reactfire,carlosCeron/reactfire,FirebaseExtended/reactfire,Wattenberger/reactfire,StevenLangbroek/reactfire,gragland/reactfire,chiefr/reactfire,FirebaseExtended/reactfire,chiefr/reactfire,Wattenberger/reactfire