Add log and dns documentation

docs/configuration/index.md

@@ -0,0 +1,37 @@
+# Introduction
+
+sing-box uses JSON for configuration files.
+
+### Structure
+
+```json
+{
+  "log": {},
+  "dns": {},
+  "inbounds": {},
+  "outbounds": {},
+  "route": {}
+}
+```
+
+### Fields
+
+| Key         | Format                 |
+|-------------|------------------------|
+| `log`       | [Log](./log)           |
+| `dns`       | [DNS](./dns)           |
+| `inbounds`  | [Inbound](./inbound)   |
+| `outbounds` | [Outbound](./outbound) |
+| `route`     | [Route](./route)       |
+
+### Check
+
+```bash
+$ sing-box check
+```
+
+### Format
+
+```bash
+$ sing-box format -w
+```