document multi-user usage of same budget file

docs-sidebar.js

@@ -226,6 +226,7 @@ const sidebars = {
           items: [
             'experimental/goal-templates',
             'experimental/monthly-cleanup',
+            'experimental/multi-user',
             'experimental/tracking-budget',
           ],
         },

docs/budgeting/joint-accounts.md

@@ -11,6 +11,7 @@ One approach is maintaining a common budget where both partners share a single b
 This method promotes transparency and ensures both parties agree regarding financial goals, expenses, and income.
 A shared budget fosters collaboration but requires consistent communication to keep everything current. It will help
 you both set clear boundaries for individual and shared expenses while working together toward common financial objectives.
+See [Multi-user](/docs/experimental/multi-user) regarding simultaneous edits.
 
 Alternatively, you can track your partner’s contributions within your personal Actual Budget file. This allows you to
 maintain individual control over your finances while still acknowledging and accounting for your partner’s financial

docs/experimental/multi-user.md

@@ -0,0 +1,9 @@
+# Multi-user
+
+:::warning
+This is an **experimental feature**. That means we’re still working on finishing it. There may be bugs, missing functionality or incomplete documentation, and we may decide to remove the feature in a future release. If you have any feedback, please [open an issue](https://github.com/actualbudget/actual/issues) or post a message in the Discord.
+:::
+
+## Multi-user Support
+
+The same budget file may be open and edited simultaneously from two separate browsers, even by two different people on different client computers. This should work unless the edits conflict. To be safe, avoid simultaneous usage of the same budget file.