added description of project

[rtl433-sensors] / README

Capture 433 Mhz sensors using rtl-sdr emit json using mqtt and save to influx/PostgreSQL


Example queryies:

        select time,model,json->'temperature_C' as temp,((abs((json->>'temperature_C')::float) - 32)/(9/5)) as f2c,json->'humidity' as hum from rtl433 where (json->>'temperature_C')::float < 200 order by time desc limit 30 ;