docs: update readme with explainations (#5)

* docs: update readme with explainations

Describe how the package works and notes for developers.

* docs: fix example destructure

* docs: additional info

readme.md

@@ -13,7 +13,7 @@
 ```ts
 import {find} from 'canadian-city-timezones';
 
-const result = await find((city, province) => city === 'Lethbridge' && province === 'Alberta');
+const result = await find(({city, province}) => city === 'Lethbridge' && province === 'Alberta');
 result.city // Lethbridge
 result.province // Alberta
 result.timezone // America/Edmonton
@@ -52,6 +52,19 @@ Yields all values.
 }
 ```
 
+## How Does This Work?
+
+Before this package is published, census data listing all dwellings in Canada is downloaded from `statcan.gc.ca`. This is filtered by applicable types (city, town, etc) and sent to `mapbox.com` to find the dwelling's geographic coordinates (latitude & longitude). From there, the coordinates are given to [`geo-tz`](https://github.com/evansiroky/node-geo-tz) which returns the timezone.
+
+This data is then written to a CSV file and published along side the simple interface for interacting with the data. So look ups are quick since it is just checking a local CSV.
+
+The interface works with an async generator, reading this CSV file line by line to avoid loading all data into memory.
+
 ## Development
 
-Timezones are generated automatically by pulling the list of areas from `gc.ca` and feeding them into `mapbox.com` to get their coordinates, then getting the timezone using [`geo-tz`](https://github.com/evansiroky/node-geo-tz).
+We want to reduce the number of dependencies the end user encounters, keep that in mind when working within this repository.
+
+Data can be generated by manually triggering [the `Generate` workflow](https://github.com/autovance/canadian-city-timezones/actions?query=workflow%3AGenerate).
+
+Releases are done automatically when commits are merged into master using [semantic-release](https://github.com/semantic-release/semantic-release). Please use appropriate commit prefixes.
+Changes that only affect the generation of data should be prefixed with `generate:` to avoid triggering a release.