Support laravel 5.8

Author: Jack97

composer.json

@@ -8,10 +8,10 @@
         }
     ],
     "require": {
-        "illuminate/database": "~5.5|~5.6|~5.7"
+        "illuminate/database": "~5.5.0|~5.6.0|~5.7.0|~5.8.0"
     },
     "require-dev": {
-        "orchestra/testbench": "~3.5|~3.6|~3.7"
+        "orchestra/testbench": "~3.5.0|~3.6.0|~3.7.0|~3.8.0"
     },
     "autoload": {
         "psr-4": {