putMapping is an HTTP PUT and has upsert semantics. Mappings
are schemas for documents in indexes.
>>> _ <- runBH' $ createIndex defaultIndexSettings testIndex
>>> resp <- runBH' $ putMapping testIndex testMapping TweetMapping
>>> print resp
Response {responseStatus = Status {statusCode = 200, statusMessage = "OK"}, responseVersion = HTTP/1.1, responseHeaders = [("content-type","application/json; charset=UTF-8"),("content-encoding","gzip"),("transfer-encoding","chunked")], responseBody = "{\"acknowledged\":true}", responseCookieJar = CJ {expose = []}, responseClose' = ResponseClose}