improve mysql readme

databases/mysql/apis/customer.md

@@ -0,0 +1,34 @@
+# Customers API
+
+All examples show cURL and [HTTPie](https://httpie.io/cli) snippets.
+
+## Adding A Customer
+
+```sh
+curl -d '{"customer_name":"Peter Paul", "branch_name":"Central Business District"}' -H 'Content-Type: application/json' http://localhost:8080/customer
+
+http POST :8080/customer customer_name="Peter Paul" branch_name="Central Business District"
+```
+
+You should expect a 204 No Content response.
+
+## Listing Customers
+
+```sh
+curl http://localhost:8080/customer
+
+http :8080/customer
+```
+
+The response should be a 200 OK with the following JSON body:
+
+```json
+{
+  "customer_data": [
+    {
+      "customer_name": "peter paul",
+      "branch_name": "central business district"
+    }
+  ]
+}
+```