Setup Firebase Environment GoogleService-Info.plist, https://medium.com/rocket-fuel/using-multiple-firebase-environments-in-ios-12b204cfa6c0

setup_firebase.sh

# Name of the resource we're selectively copying
GOOGLESERVICE_INFO_PLIST=GoogleService-Info.plist

# Get references to dev and prod versions of the GoogleService-Info.plist
# NOTE: These should only live on the file system and should NOT be part of the target (since we'll be adding them to the target manually)
GOOGLESERVICE_INFO_DEV=${PROJECT_DIR}/${TARGET_NAME}/Firebase/Debug/${GOOGLESERVICE_INFO_PLIST}
GOOGLESERVICE_INFO_STAGING=${PROJECT_DIR}/${TARGET_NAME}/Firebase/Staging/${GOOGLESERVICE_INFO_PLIST}
GOOGLESERVICE_INFO_PROD=${PROJECT_DIR}/${TARGET_NAME}/Firebase/Release/${GOOGLESERVICE_INFO_PLIST}

# Make sure the dev version of GoogleService-Info.plist exists
echo "Looking for ${GOOGLESERVICE_INFO_PLIST} in ${GOOGLESERVICE_INFO_DEV}"
if [ ! -f $GOOGLESERVICE_INFO_DEV ]
then
echo "No Development GoogleService-Info.plist found. Please ensure it's in the proper directory."
exit 1
fi

# Make sure the staging version of GoogleService-Info.plist exists
echo "Looking for ${GOOGLESERVICE_INFO_PLIST} in ${GOOGLESERVICE_INFO_STAGING}"
if [ ! -f $GOOGLESERVICE_INFO_STAGING ]
then
echo "No Stating GoogleService-Info.plist found. Please ensure it's in the proper directory."
exit 1
fi

# Make sure the prod version of GoogleService-Info.plist exists
echo "Looking for ${GOOGLESERVICE_INFO_PLIST} in ${GOOGLESERVICE_INFO_PROD}"
if [ ! -f $GOOGLESERVICE_INFO_PROD ]
then
echo "No Production GoogleService-Info.plist found. Please ensure it's in the proper directory."
exit 1
fi

# Get a reference to the destination location for the GoogleService-Info.plist
PLIST_DESTINATION=${BUILT_PRODUCTS_DIR}/${PRODUCT_NAME}.app
echo "Will copy ${GOOGLESERVICE_INFO_PLIST} to final destination: ${PLIST_DESTINATION}"

# Copy over the prod GoogleService-Info.plist for Release builds
if [ "${CONFIGURATION}" == "Release" ]
then
echo "Using ${GOOGLESERVICE_INFO_PROD}"
cp "${GOOGLESERVICE_INFO_PROD}" "${PLIST_DESTINATION}"
elif [ "${CONFIGURATION}" == "Staging" ]
then
echo "Using ${GOOGLESERVICE_INFO_STAGING}"
cp "${GOOGLESERVICE_INFO_STAGING}" "${PLIST_DESTINATION}"
else
echo "Using ${GOOGLESERVICE_INFO_DEV}"
cp "${GOOGLESERVICE_INFO_DEV}" "${PLIST_DESTINATION}"
fi