Adding models, DB access, signup, login

* Created Base, Auth, User and Admin models
* Added skeleton API structure containing: User signup, User & Admin
login, authorized zones, ping tests
* Simple user signup functional
* Skeleton user login functional, no means to verify as of yet
* Added POSTMAN file

.gitignore

@@ -13,3 +13,7 @@
 
 # Dependency directories (remove the comment below to include it)
 # vendor/
+
+# Other
+prepack.db
+test_prepack.db