Update README for setting up Initial Index with Bonsai

[tinashe96]

curl -X POST <BONSAI_URL>/firebase produces the following error:

{"error":"Incorrect HTTP method for uri [/firebase] and method [POST], allowed: [GET, HEAD, DELETE, PUT]","status":405}

However, curl -X PUT <BONSAI_URL>/firebase works just fine.

I don't know the technical reason behind this but judging by the error message, POST cannot be used as the method.

[emgould]

Same issue here. Did you resolve this?

[tinashe96]

@emgould using PUT instead of POST worked for me