description for --dynamic-whitelist moved to new docs/deprecated.md

docs/deprecated.md

@@ -0,0 +1,31 @@
+# Deprecated features
+
+This page contains description of the command line arguments, configuration parameters
+and the bot features that were declared as DEPRECATED by the bot development team
+and are no longer supported. Please avoid their usage in your configuration.
+
+### The **--dynamic-whitelist** command line option
+
+Per default `--dynamic-whitelist` will retrieve the 20 currencies based
+on BaseVolume. This value can be changed when you run the script.
+
+**By Default**
+Get the 20 currencies based on BaseVolume.
+
+```bash
+python3 ./freqtrade/main.py --dynamic-whitelist
+```
+
+**Customize the number of currencies to retrieve**
+Get the 30 currencies based on BaseVolume.
+
+```bash
+python3 ./freqtrade/main.py --dynamic-whitelist 30
+```
+
+**Exception**
+`--dynamic-whitelist` must be greater than 0. If you enter 0 or a
+negative value (e.g -2), `--dynamic-whitelist` will use the default
+value (20).
+
+