Block/allow DM reminders

Only affects slash commands but this is sort of a non-issue post September

src/models/reminder/builder.rs

@@ -233,6 +233,10 @@ impl<'a> MultiReminderBuilder<'a> {
                             if let Some(guild_id) = self.guild_id {
                                 if guild_id.member(&self.ctx.discord(), user).await.is_err() {
                                     Err(ReminderError::InvalidTag)
+                                } else if self.set_by.map_or(true, |i| i != user_data.id)
+                                    && !user_data.allowed_dm
+                                {
+                                    Err(ReminderError::UserBlockedDm)
                                 } else {
                                     Ok(user_data.dm_channel)
                                 }

src/models/reminder/errors.rs

@@ -7,6 +7,7 @@ pub enum ReminderError {
     PastTime,
     ShortInterval,
     InvalidTag,
+    UserBlockedDm,
     DiscordError(String),
 }
 
@@ -30,6 +31,9 @@ impl ToString for ReminderError {
             ReminderError::InvalidTag => {
                 "Couldn't find a location by your tag. Your tag must be either a channel or a user (not a role)".to_string()
             }
+            ReminderError::UserBlockedDm => {
+                "User has DM reminders disabled".to_string()
+            }
             ReminderError::DiscordError(s) => format!("A Discord error occurred: **{}**", s),
         }
     }