Add invite creation, removal, fetch and usage.

src/database/guild.rs

@@ -16,8 +16,8 @@ pub struct Member {
 
 #[derive(Serialize, Deserialize, Debug)]
 pub struct Invite {
-    pub id: String,
-    pub custom: bool,
+    pub code: String,
+    pub creator: String,
     pub channel: String,
 }
 

src/database/permissions.rs

@@ -137,7 +137,7 @@ impl PermissionCalculator {
         };
 
         if let Some(guild) = &guild {
-            self.member = get_member(guild, &self.user.id);
+            self.member = get_member(&guild.id, &self.user.id);
         }
 
         self.guild = guild;