Adds HACKING.md

HACKING.md

@@ -0,0 +1,12 @@
+# Generating the regex
+
+1. Download the latest CSV file from <https://data.gov.in/node/85839/download> or <https://data.gov.in/resources/all-india-pincode-directory>.
+2. Copy all the pincodes to a pincodes.txt file
+3. Generate all unique pincodes by running `sort -u pincodes.txt > /tmp/pin.txt`
+4. `npm install`
+5. `node src/generate.js /tmp/pin.txt > regex.txt`
+
+# PHP Release
+
+1. `git tag 1.2.3`
+2. `git push --tags`

README.md

@@ -21,6 +21,11 @@ use PIN\Validator as P;
 P::validate('110011'); // returns true;
 ```
 
+## Contributing
+
+- See [`HACKING.md`](HACKING.md) for some development details.
+- Pull requests are welcome for adding libraries in other languages (in the same repo).
+
 ## License
 
 Licensed under the [MIT License](https://nemo.mit-license.org/). See LICENSE file for details.