Update readme with user stories

#### User Stories

- [ ] As a user, I want to be able to select a letter and get the list of available domain starting with that letter.

- [ ] As a user, I want to be able to select the number of letters from drop down box and get the list of domain names.

- [ ] As a user, I want to be able to select the tld/gtld from the drop down box and get the random list of available domain names.

- [ ] As a user, I want to be able to type in a domain name with tld/gtld and get immediate results, whether or not the domain is available.

- [ ] As a user, I want to be able to click on the domain mame which redirects me to the domain seller page (Gandhi.net, or some other)