Document usage

Author: markhobson

README.md

@@ -1,2 +1,18 @@
-# docker-sqlpackage
-Docker image for sqlpackage
+# markhobson/sqlpackage
+
+Docker image for [sqlpackage](https://docs.microsoft.com/en-us/sql/tools/sqlpackage-download) 18.4.
+
+## Usage
+
+To run sqlpackage:
+
+```bash
+docker run -it --rm markhobson/sqlpackage sqlpackage
+```
+
+To import a bacpac file `/bacpacs/db.bacpac` to `Server=tcp:localhost,1433;Initial Catalog=db;User ID=sa;Password=password;`:
+
+```bash
+docker run -it --rm -v /bacpacs:/host --network=host sqlpackage \
+    sqlpackage /a:Import /tsn:tcp:localhost /tdn:db /tu:sa /tp:password /sf:/host/db.bacpac
+```