Add documentation and changelog

changelog/unreleased/pull-2350

@@ -0,0 +1,8 @@
+Enhancement: Add option to configure S3 region
+
+We've added a new option for setting the region when accessing an S3-compatible
+service. For some providers, it is required to set this to a valid value. You
+can do that either by setting the environment variable `AWS_REGION` or using
+the option `s3.region`, e.g. like this: `-o s3.region="us-east-1"`.
+
+https://github.com/restic/restic/pull/2350

doc/030_preparing_a_new_repo.rst

@@ -197,10 +197,11 @@ default location:
     Please note that knowledge of your password is required to access the repository.
     Losing your password means that your data is irrecoverably lost.
 
-It is not possible at the moment to have restic create a new bucket in a
-different location, so you need to create it using a different program.
-Afterwards, the S3 server (``s3.amazonaws.com``) will redirect restic to
-the correct endpoint.
+If needed, you can manually specify the region to use by either setting the
+environment variable ``AWS_REGION`` or calling restic with an option parameter
+like ``-o s3.region="us-east-1"``. If the region is not specified, the default
+region is used. Afterwards, the S3 server (``s3.amazonaws.com``) will redirect
+restic to the correct endpoint.
 
 Until version 0.8.0, restic used a default prefix of ``restic``, so the files
 in the bucket were placed in a directory named ``restic``. If you want to