Add PHPUnit

Author: mathleite

composer.json

@@ -16,5 +16,16 @@
         "psr-4": {
             "App\\": "app"
         }
+    },
+    "autoload-dev": {
+        "psr-4": {
+            "App\\Test\\": "tests"
+        }
+    },
+    "require-dev": {
+        "phpunit/phpunit": "8.5.*"
+    },
+    "scripts": {
+        "tests": "./vendor/bin/phpunit tests --color=always --stop-on-failure"
     }
 }