docs: add testing info to readme (#301)

* refactor: Upgrade to Gorm 2.0

* Clean up dependencies

* Fix linting errors

Remove gorm v1 delete callback

* Resolve unittest failures

* Fix association query

* Add testing section to readme

Co-authored-by: Jordan Craven <jordan.craven@wearepop.com>

README.md

@@ -34,6 +34,7 @@ Features include: independence of users and hosts, convenient user invite system
 - [portal alias (.ssh/config)](#portal-alias-sshconfig)
 - [Scaling](#scaling)
 - [Under the hood](#under-the-hood)
+- [Testing](#testing)
 
 <!-- tocstop -->
 
@@ -472,6 +473,26 @@ See [examples/mysql](http://github.com/moul/sshportal/tree/master/examples/mysql
 
 ![sshportal data model](https://raw.github.com/moul/sshportal/master/.assets/sql-schema.png)
 
+---
+
+## Testing
+
+[Install golangci-lint](https://golangci-lint.run/usage/install/#local-installation) and run this in project root: 
+```
+golangci-lint run
+```
+---
+Perform integration tests
+```
+make integration
+```
+---
+Perform unit tests
+```
+make unittest
+```
+---
+
 ## Contributors
 
 ### Code Contributors