Organise existing documentation into a tree structure.

SUMMARY.md defines the sidebar of the website. We organise existing documentation
into a logical structure. We also add a couple of pages which make use of mdbook's
file include feature to include existing documentation that typically lives
outside of the docs/ directory. We also use it to combine the sample config files
into a single page with surrounding contextual info.

2 files changed, 83 insertions, 0 deletions

diff --git a/docs/SUMMARY.md b/docs/SUMMARY.md
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+++ b/docs/SUMMARY.md
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+# Summary
+
+- [Introduction](welcome_and_overview.md)
+- [Setup]()
+  - [Installation](setup/installation.md)
+  - [Using Postgres](postgres.md)
+  - [Configuring a Reverse Proxy](reverse_proxy.md)
+  - [Configuring a Turn Server](turn-howto.md)
+  - [Delegation](delegate.md)
+- [Upgrading](upgrading/README.md)
+  - [Upgrading from pre-Synapse 1.0](MSC1711_certificates_FAQ.md)
+- [Usage]()
+  - [Federation](federate.md)
+  - [Configuration]()
+    - [Sample Configuration Files](usage/configuration/sample_config.md)
+    - [User Authentication]()
+      - [Single-Sign On]()
+        - [OpenID Connect](openid.md)
+        - [SAML]()
+        - [CAS]()
+        - [SSO Mapping Providers](sso_mapping_providers.md)
+      - [Password Auth Providers](password_auth_providers.md)
+      - [JSON Web Tokens](jwt.md)
+    - [Registration Captcha](CAPTCHA_SETUP.md)
+    - [Application Services](application_services.md)
+    - [Server Notices](server_notices.md)
+    - [Consent Tracking](consent_tracking.md)
+    - [URL Previews](url_previews.md)
+    - [User Directory](user_directory.md)
+    - [Message Retention Policies](message_retention_policies.md)
+    - [Pluggable Modules]()
+      - [Third Party Rules]()
+      - [Spam Checker](spam_checker.md)
+      - [Presence Router](presence_router_module.md)
+      - [Writing a Module]()
+    - [Workers](workers.md)
+      - [Using `synctl` with Workers](synctl_workers.md)
+      - [Systemd](systemd-with-workers/README.md)
+  - [Administration]()
+    - [Admin API](admin_api/README.rst)
+      - [Account Validity](admin_api/account_validity.rst)
+      - [Delete Group](admin_api/delete_group.md)
+      - [Event Reports](admin_api/event_reports.md)
+      - [Media](admin_api/media_admin_api.md)
+      - [Purge History](admin_api/purge_history_api.rst)
+      - [Purge Rooms](admin_api/purge_room.md)
+      - [Register Users](admin_api/register_api.rst)
+      - [Manipulate Room Membership](admin_api/room_membership.md)
+      - [Rooms](admin_api/rooms.md)
+      - [Server Notices](admin_api/server_notices.md)
+      - [Shutdown Room](admin_api/shutdown_room.md)
+      - [Statistics](admin_api/statistics.md)
+      - [Users](admin_api/user_admin_api.rst)
+      - [Server Version](admin_api/version_api.rst)
+    - [Manhole](manhole.md)
+    - [Monitoring](metrics-howto.md)
+    - [Structured Logging](structured_logging.md)
+    - [Scripts]()
+- [Development]()
+  - [Contributing Guide](development/contributing_guide.md)
+  - [Code Style](code_style.md)
+  - [Git Usage](dev/git.md)
+  - [Testing]()
+  - [OpenTracing](opentracing.md)
+  - [Synapse Architecture]()
+    - [Log Contexts](log_contexts.md)
+    - [Replication](replication.md)
+    - [TCP Replication](tcp_replication.md)
+  - [Feature Documentation]()
+    - [Single Sign-On]()
+      - [SAML](dev/saml.md)
+      - [CAS](dev/cas.md)
+    - [State Resolution]()
+      - [The Auth Chain Difference Algorithm](auth_chain_difference_algorithm.md)
+    - [Media Repository](media_repository.md)
+    - [Room and User Statistics](room_and_user_statistics.md)
+  - [Scripts]()
+- [Other]()
+  - [Dependency Deprecation Policy](deprecation_policy.md)
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diff --git a/docs/welcome_and_overview.md b/docs/welcome_and_overview.md
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@@ -0,0 +1,4 @@
+# Introduction
+
+Welcome to the documentation repository for Synapse, the reference
+[Matrix](https://matrix.org) homeserver implementation.
\ No newline at end of file