update documentation

documentation/commands.md

@@ -278,4 +278,24 @@ followed by the date, followed by the transaction hash.
 As an example, you can use `set-transaction-sort-order BY_DATE_THEN_COINS_ABSOLUTE_THEN_HASH` to sort by date
 (and then by absolute coin value if two transactions have the same date).
 Please use [tab completion](#tab-completion) (type `set-transaction-sort-order` and press TAB twice) to see all
-available sort orders.
+available sort orders.
+
+## Forks
+You can also select the BCH (Bitcoin Cash) and BSV (Bitcoin SV) chains, enabling you to track coins in these chains.
+To do that, run `select-chain BCH` or `select-chain BSV` and use BitBook as before:
+
+```
+BitBook₿ select-chain BCH
+BitBook(BCH)₿
+```
+
+You can switch chains arbitrarily. The selected chain is shown in the prompt and used for all future commands, most
+notably `get-neighbour-transactions`.
+
+Existing information for transactions also valid in the selected chain (because they were confirmed before the fork)
+is retained and reused.
+Ownership information for addresses is considered irrespectively of any chain, based on the assumption that you know the
+private keys.
+
+Note that, currently, there is no price information available for non-BTC coins, although prices are shown for blocks up
+to the fork date.

documentation/ideas.md

@@ -1,10 +1,4 @@
 # Future Ideas
-## Forks
-It may be helpful to be able to answer questions like "How many Bitcoin Cash do I have, and where?"
-for forks like Bitcoin Cash, Bitcoin Gold, ... that share parts of their blockchain with Bitcoin.
-This can be done by making use of the block height information (before/after a fork?), and making the
-code fork-aware.
-
 ## Interactive CLI
 Running `get-neighbour-transactions` and the other commands repeatedly is quite frustrating.
 BitBook should offer an interactive mode that guides the user to completion.