how_to_clear_an_elasticsearch_index_in_ruby.rb

# Fetch all the "mapping" from elasticsearch using the enpoint 
# "/_mapping" and saved them on mapping.json file
# curl http://localhost:9200/_mapping

# parse the results fetched and saved into mapping.json and we iterate over 
# the parent index names and start to call the endpoint for delete them
require "json"
keys = JSON.parse(`curl http://localhost:9200/_mapping`).keys
keys.each {|key| `curl -XDELETE http://localhost:9200/#{key}`}