README: Document fish shell prompt customization

diff --git a/README.md b/README.md
index 0a0f9d9..8058590 100644 (file)
--- a/README.md
+++ b/README.md
@@ -123,6 +123,16 @@ In your `.zshrc`, you should add something like:
 export PROMPT="$GST_ENV-$PROMPT"
 ```
 
+### Fish prompt
+
+In your `~/.config/fish/functions/fish_prompt.fish`, you should add something like this at the end of the fish_prompt function body:
+
+```
+if set -q GST_ENV
+  echo -n -s (set_color -b blue white) "(" (basename "$GST_ENV") ")" (set_color normal) " "
+end
+```
+
 ### Using powerline
 
 In your powerline theme configuration file (by default in