added btcpay pairing instructions to readme

README.md

@@ -45,9 +45,8 @@ Run the app
 FLASK_APP=capsulflask flask run
 ```
 
-Run the app in gunicorn locally
+Run the app in gunicorn
 ```
-pip install gunicorn
 .venv/bin/gunicorn --bind 127.0.0.1:5000 capsulflask:app
 ```
 
@@ -61,3 +60,61 @@ For example, the script named `02_up_xyz.sql` should contain code that migrates
 **IMPORTANT: if you need to make changes to the schema, make a NEW schema version. DO NOT EDIT the existing schema versions.**
 
 In general, for safety, schema version upgrades should not delete data. Schema version downgrades will simply throw an error and exit for now. 
+
+
+## how to setup btcpay server
+
+Generate a private key and the accompanying bitpay SIN for the bitpay API client. 
+
+  I used this code as an example: https://github.com/bitpay/bitpay-python/blob/master/bitpay/key_utils.py#L6
+
+```
+$ python ./readme/generate_btcpay_keys.py
+```
+
+It should output something looking like this:
+
+```
+-----BEGIN EC PRIVATE KEY-----
+EXAMPLEIArx/EXAMPLEKH23EXAMPLEsYXEXAMPLE5qdEXAMPLEcFHoAcEXAMPLEK
+oUQDQgAEnWs47PT8+ihhzyvXX6/yYMAWWODluRTR2Ix6ZY7Z+MV7v0W1maJzqeqq
+NQ+cpBvPDbyrDk9+Uf/sEaRCma094g==
+-----END EC PRIVATE KEY-----
+
+
+EXAMPLEwzAEXAMPLEEXAMPLEURD7EXAMPLE
+```
+
+In order to register the key with the btcpay server, you have to first generate a pairing token using the btcpay server interface.
+This requires your btcpay server account to have access to the capsul store. Ask Cass about this.
+
+Navigate to `Manage store: Access Tokens` at: `https://btcpay.cyberia.club/stores/<store-id>/Tokens`
+
+![](readme/btcpay_sin_pairing.jpg)
+
+
+Finally, send an http request to the btcpay server to complete the pairing:
+
+```
+curl -H "Content-Type: application/json" https://btcpay.cyberia.club/tokens -d "{'id': 'EXAMPLEwzAEXAMPLEEXAMPLEURD7EXAMPLE', 'pairingCode': 'XXXXXXX'}"
+```
+
+It should respond with a token: 
+
+```
+{"data":[{"policies":[],"pairingCode":"XXXXXXX","pairingExpiration":1589473817597,"dateCreated":1589472917597,"facade":"merchant","token":"xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx","label":"capsulflask"}]}
+```
+
+And you should see the token in the btcpay server UI:
+
+![](readme/paired.jpg)
+
+Now simply set your BTCPAY_PRIVATE_KEY private key in `.env`
+
+```
+BTCPAY_PRIVATE_KEY='-----BEGIN EC PRIVATE KEY-----
+EXAMPLEIArx/EXAMPLEKH23EXAMPLEsYXEXAMPLE5qdEXAMPLEcFHoAcEXAMPLEK
+oUQDQgAEnWs47PT8+ihhzyvXX6/yYMAWWODluRTR2Ix6ZY7Z+MV7v0W1maJzqeqq
+NQ+cpBvPDbyrDk9+Uf/sEaRCma094g==
+-----END EC PRIVATE KEY-----'
+```