Add missing permissions utilities

src/http/permissions.rs

@@ -0,0 +1,17 @@
+use crate::ayb_db::models::{InstantiatedDatabase, InstantiatedEntity};
+
+pub fn can_create_database(
+    authenticated_entity: &InstantiatedEntity,
+    desired_entity: &InstantiatedEntity,
+) -> bool {
+    // An entity/user can only create databases on itself (for now)
+    return authenticated_entity.id == desired_entity.id;
+}
+
+pub fn can_query(
+    authenticated_entity: &InstantiatedEntity,
+    database: &InstantiatedDatabase,
+) -> bool {
+    // An entity/user can only query its own databases (for now)
+    return authenticated_entity.id == database.entity_id;
+}