Provide a link to a live sandbox environment where sequelizse examples are available

We have built a 'sequelize' channel in our platform and populated it with the examples contained in your examples directory. This pull request is for adding a link to these examples on the main README.md of the SDK's github repo. Let me know if you have any feedback/questions! 

PS: I also updated the examples to the correct config location (inside spec vs non-existent test directory).