added gitignore

.env

-SKIP_PREFLIGHT_CHECK=true
\ No newline at end of file

.env.example

-REACT_APP_API_KEY=XXXXxxxx
-REACT_APP_AUTH_DOMAIN=xxxxXXXX.firebaseapp.com
-REACT_APP_DATABASE_URL=https://xxxXXXX.firebaseio.com
-REACT_APP_PROJECT_ID=xxxxXXXX
-REACT_APP_STORAGE_BUCKET=xxxxXXXX.appspot.com
-REACT_APP_MESSAGING_SENDER_ID=xxxxXXXX
\ No newline at end of file

.gitignore

 node_modules
+package-lock.json
+yarn.lock
+.env*
+.DS*