Add docs for database restore params and config bootstrap (#326, #697).

Merge pull request #74 from diivi/docs/database-restore-params-and-config-bootstrap

docs/how-to/backup-your-databases.md

@@ -338,6 +338,28 @@ within the database dump:
 borgmatic restore --archive latest --database users --schema tentant1
 ```
 
+### Restore to an alternate host
+<span class="minilink minilink-addedin">New in version 1.7.15</span>
+A database dump can be restored to a host other than the one from which it was
+originally dumped. The connection parameters like the username, password, and
+port can also be changed. This can be done from the command line:
+
+```bash
+borgmatic restore --archive latest --database users --hostname database2.example.org --port 5433 --username postgres --password trustsome1
+```
+
+Or from the configuration file:
+
+```yaml
+postgresql_databases:
+    - name: users
+        hostname: database1.example.org
+        restore_hostname: database1.example.org
+        restore_port: 5433
+        restore_username: postgres
+        restore_password: trustsome1
+```
+
 
 ### Limitations
 

docs/how-to/extract-a-backup.md

@@ -44,7 +44,6 @@ entire contents of the archive to the current directory, so make sure you're
 in the right place before running the command—or see below about the
 `--destination` flag.
 
-
 ## Repository selection
 
 If you have a single repository in your borgmatic configuration file(s), no
@@ -145,3 +144,29 @@ When you're all done exploring your files, unmount your mount point. No
 ```bash
 borgmatic umount --mount-point /mnt
 ```
+
+## Extract the configuration files used to create an archive
+
+<span class="minilink minilink-addedin">New in version 1.7.15</span> borgmatic
+automatically stores all the configuration files used to create an archive inside the
+archive itself. This is useful in cases where you've lost a configuration
+file or you want to see what configurations were used to create a particular
+archive.
+
+To extract the configuration files from an archive, use the `config bootstrap` action. For example:
+
+```bash 
+borgmatic config bootstrap --repository repo.borg --destination /tmp
+```
+
+This extracts the configuration file from the latest archive in the repository `repo.borg` to `/tmp/etc/borgmatic/config.yaml`, assuming that the only configuration file used to create this archive was located at `/etc/borgmatic/config.yaml` when the archive was created.
+
+Note that to run the `config bootstrap` action, you don't need to have a borgmatic configuration file. You only need to specify the repository to use via the `--repository` flag; borgmatic will figure out the rest.
+
+If a destination directory is not specified, the configuration files will be extracted to their original locations, silently **overwriting** any configuration files that may already exist. For example, if a configuration file was located at `/etc/borgmatic/config.yaml` when the archive was created, it will be extracted to `/etc/borgmatic/config.yaml` too.
+
+If you want to extract the configuration file from a specific archive, use the `--archive` flag:
+
+```bash
+borgmatic config bootstrap --repository repo.borg --archive host-2023-01-02T04:06:07.080910 --destination /tmp
+```