Improve README

Author: mbark

README.md

@@ -4,7 +4,10 @@ Your task is to create a server that exposes an API to manage subscriptions, cre
 
 ## Description
 
-Your server should support:
+Your server should expose an API via either [`REST`](https://en.wikipedia.org/wiki/Representational_state_transfer)
+or [`graphql`](https://graphql.org/).
+
+The API should support:
 
 * creating a new subscription for a `msisdn` with an `activate_at` date and a type;
     * if a non-cancelled subscription already has the same `msisdn` the request should be rejected;
@@ -23,7 +26,7 @@ A subscription represents a user's phone subscription, which has the following i
 * [`msisdn`](https://en.wikipedia.org/wiki/MSISDN) which is the subscription's number;
 * `activate_at` which is the date when the subscription is activated in the system;
 * `type` which is either [`PBX`](https://en.wikipedia.org/wiki/Business_telephone_system#Private_branch_exchange)
-  or `CELL`;
+  or [`CELL`](https://en.wikipedia.org/wiki/Mobile_phone);
 * `status` which is one of `pending`, `activated`, `paused` or `cancelled`.
 
 ## Submission
@@ -36,7 +39,7 @@ technical skills._
 
 ## Requirements
 
-* Your submission should include a `README.md` file documenting how to install and start the project;
+* Your submission should include a `README.md` file documenting how to install start and test the project;
 * You won't have the time to make everything perfect, just document what is lacking and how you would improve it;
 * Do not make the task harder than it is, it should take a couple of hours but absolutely not more than 8 hours;
 * You are free to use any technology and framework of your choice.