[skip ci] Merge pull request #726 from bgarret/patch-1

Improve the Zero SSL documentation

docs/Zero-SSL.md

@@ -6,9 +6,17 @@
 
 Using Zero SSL through an ACME client, like in this container, allows for unlimited 90 days and multi-domains (SAN) certificates.
 
+### Activation
+
+The Zero SSL support is activated when the `ACME_CA_URI` environment variable is set to the Zero SSL ACME endpoint (`https://acme.zerossl.com/v2/DV90`).
+
+### Account
+
 Unlike Let's Encrypt, Zero SSL requires the use of an email bound account. If you already created a Zero SSL account, you can either:
 
-- provide pre generated [EAB credentials](https://tools.ietf.org/html/rfc8555#section-7.3.4) using the `ACME_EAB_KID` and `ACME_EAB_HMAC_KEY` environement variables.
-- provide your ZeroSSL API key using the `ZEROSSL_API_KEY` environement variable.
+- provide pre-generated [EAB credentials](https://tools.ietf.org/html/rfc8555#section-7.3.4) using the `ACME_EAB_KID` and `ACME_EAB_HMAC_KEY` environment variables.
+- provide your ZeroSSL API key using the `ZEROSSL_API_KEY` environment variable.
+
+These variables can be set on the proxied containers or directly on the **letsencrypt-nginx-proxy-companion** container.
 
 If you don't have a ZeroSSL account, you can let **letsencrypt-nginx-proxy-companion** create a Zero SSL account with the adress provided in the `ACME_EMAIL` or `DEFAULT_EMAIL` environment variable. Note that the adresse that will be used must be a valid email adress that you actually own.