[feature] Allow import of following and blocks via CSV (#3150)

* [feature] Import follows + blocks via settings panel

* test import follows

2 files changed, 36 insertions, 4 deletions

diff --git a/docs/user_guide/migration.md b/docs/user_guide/migration.md
index 8d37a0869..a2d2a4c36 100644
--- a/docs/user_guide/migration.md
+++ b/docs/user_guide/migration.md
@@ -74,5 +74,5 @@ Once you have triggered the move from your other account to your GoToSocial acco
 !!! tip
     To save yourself some trouble, consider setting your GoToSocial account to not require approval for new follow requests, just before triggering the migration. Once the migration is complete, turn approval of follow requests back on. Otherwise, you will have to manually approve every migrated follower from your old account.
 
-!!! warning
-    While the move will indicate to your followers that they should follow you at your GoToSocial account, GoToSocial does not yet support importing a list of accounts you follow. Until we implement this, you will have to manually follow accounts again from your GoToSocial account. Please see [this issue](https://github.com/superseriousbusiness/gotosocial/issues/1048) for more details.
+!!! tip
+    After moving your account, you may wish to import your list of followed accounts from your previous account into your GoToSocial account. [See here](./settings.md#import) for details on how to do this via the settings panel.
diff --git a/docs/user_guide/settings.md b/docs/user_guide/settings.md
index 0811381c0..ed069c19c 100644
--- a/docs/user_guide/settings.md
+++ b/docs/user_guide/settings.md
@@ -207,8 +207,40 @@ Please see the [migration document](./migration.md) for more information on movi
 
 ## Export & Import
 
-In the export & import section, you can export data from your GoToSocial account, or import data into it (TODO).
+In the export & import section, you can export data from your GoToSocial account, or import data into it.
+
+![The export/import page.](../assets/user-settings-export-import.png)
 
 ### Export
 
-To export your following, followers, lists, account blocks, or account mutes, you can use the button on this page. All exports will be served in Mastodon-compatible CSV format, so you can import them later into Mastodon or another GoToSocial instance, if you like.
+To export your following, followers, lists, account blocks, or account mutes, you can use the button on this page.
+
+All exports will be served in Mastodon-compatible CSV format, so you can import them later into Mastodon or another GoToSocial instance, if you like.
+
+### Import
+
+You can use the import section to import data from another account into your GoToSocial account, using CSV files exported from the other account.
+
+This is useful in cases where you've [migrated your account](./migration.md) to a GoToSocial account, and you want to keep your list of accounts that you followed, blocked, etc., on your previous account.
+
+To import data into your account, first click on "Browse" and select a Mastodon-compatible CSV file [exported from Mastodon](https://docs.joinmastodon.org/user/moving/#export) or another compatible instance.
+
+Then, use the drop-down selector to pick what kind of data you are uploading via the CSV file.
+
+!!! warning
+    Be careful when selecting "type" or you may end up accidentally blocking a bunch of accounts you meant to follow, or vice versa!
+
+Then choose whether you want to either **merge** the new data with the existing data of that type on your GoToSocial account, or whether you want to **overwrite** existing data of that type with the data contained in the CSV file.
+
+If you choose **merge**, then any data contained in the CSV file will be added to existing data without removing any of that existing data.
+
+For example, if you follow `account1`, and `account2` from your GoToSocial account, and you're uploading a CSV file containing follows of `account3`, and `account4`, and using mode **merge**, then at the end of the import you will be following `account1`, `account2`, `account3`, and `account4`.
+
+If you choose **overwrite**, then any data contained in the CSV file will *replace* the existing data, by removing entries not contained in the CSV file.
+
+For example, if you follow `account1`, and `account2` from your GoToSocial account, and you're uploading a CSV file containing follows of `account3`, and `account4`, and using mode **overwrite**, then at the end of the import you will be following `account3`, and `account4`. Your follows of `account1` and `account2` will be removed.
+
+Both merge and overwrite operations are idempotent, which basically means that duplicate entries in the existing data and in the CSV file are not an issue, and you can do imports of the same data multiple times if you need to retry importing for whatever reason.
+
+!!! info
+    For a variety of reasons, it will not always be possible to recreate every entry in an uploaded CSV file via importing. For example, say you are trying to import a CSV of follows containing `example_account`, but `example_account`'s instance has gone offline, or their instance blocks yours, or your instance blocks theirs, etc. In this case, the follow of `example_account` would not be created.