Update readme documentation

README.md

@@ -1,7 +1,7 @@
 # VanityGen
 Powerful PIVX VanityGen written in Rust.
 
-## Usage
+## VanityGen Usage
 ```bash
 # Choose a target prefix for your address: defaults to "D" for non-vanity mode
 --target="D<string>" # example: --target=DLabs
@@ -17,3 +17,22 @@ A full example may look like:
 ```
 ./pivx-vanity --case-insensitive --threads=6 --target=DLabs
 ```
+
+## PIVX Promos Usage
+
+As well as having VanityGen: this binary supports PIVX Promos!
+
+To create a PIVX Promos code, simply specify the quantity of codes to create, and VanityGen will shift to generating Promo Codes, ignoring VanitGen commands.
+
+```bash
+# Choose the quantity of codes to create: if not specified, VanityGen is used
+--promo-count=<int> # example: --promo-count=6
+
+# Choose a prefix for your PIVX Promo code: defaults to "PIVX Labs"
+--promo-prefix="<string>" # example: --promo-prefix="I love PIVX!"
+```
+
+A full example may look like:
+```
+./pivx-vanity --promo-count=1 --promo-prefix="JSKitty is awesome"
+```