CONTRIBUTING: Add note about testing locally (#1014)

* CONTRIBUTING: Add note about testing locally

* add podman

* Update CONTRIBUTING.md

Co-authored-by: lance6716 <[email protected]>

---------

Co-authored-by: lance6716 <[email protected]>

Author: dveeden

CONTRIBUTING.md

@@ -15,3 +15,38 @@
 ## Asking for help
 
 - Don't be afraid to ask for help in an issue or PR.
+
+## Testing
+
+Testing is done with GitHub actions.
+
+If you want to run test locally you can use the following flags:
+
+```
+  -db string
+  -host string
+  -pass string
+  -port string
+  -user string
+```
+
+Example:
+```
+$ cd client
+$ go test -args -db test2 -port 3307
+```
+
+Testing locally with Docker or Podman can be done like this:
+```
+podman run \
+--rm \
+--env MYSQL_ALLOW_EMPTY_PASSWORD=1 \
+--env MYSQL_ROOT_HOST='%' \
+-p3307:3306 \
+-it \
+container-registry.oracle.com/mysql/community-server:8.0 \
+--gtid-mode=ON \
+--enforce-gtid-consistency=ON
+```
+
+Substitude `podman` with `docker` if you're using docker. This uses `--rm` to remove the container when it stops. It also enabled GTID by passing options to `mysqld`.