Adds timeseries overview. (#1853)

Author: Simon Prickett

packages/time-series/README.md

@@ -1,3 +1,7 @@
 # @node-redis/time-series
 
-The sources and docs for this package are in the main [node-redis](https://github.com/redis/node-redis) repo.
+This package provides support for the [RedisTimeSeries](https://redistimeseries.io) module, which adds a time series data structure to Redis. It extends the [Node Redis client](https://github.com/redis/node-redis) to include functions for each of the RedisTimeSeries commands.
+
+To use these extra commands, your Redis server must have the RedisTimeSeries module installed.
+
+For an example of how to add values to a time series, query a time series, and perform aggregated queries against a time series, see `time-series.js` in the Node Redis examples folder.