Adds tab completion for the creation command, and fixes several bugs

src/main/java/net/knarcraft/permissionsigns/PermissionSigns.java

@@ -5,8 +5,10 @@ import net.knarcraft.permissionsigns.command.PermissionSignsTabCompleter;
 import net.knarcraft.permissionsigns.container.PermissionSign;
 import net.knarcraft.permissionsigns.container.SignCreationRequest;
 import net.knarcraft.permissionsigns.formatting.Translator;
+import net.knarcraft.permissionsigns.listener.SignListener;
 import net.knarcraft.permissionsigns.manager.EconomyManager;
 import net.knarcraft.permissionsigns.manager.PermissionManager;
+import net.knarcraft.permissionsigns.manager.SignManager;
 import net.knarcraft.permissionsigns.thread.SignCreationRequestTimeoutThread;
 import net.milkbowl.vault.economy.Economy;
 import net.milkbowl.vault.permission.Permission;
@@ -19,6 +21,7 @@ import org.bukkit.plugin.ServicesManager;
 import org.bukkit.plugin.java.JavaPlugin;
 import org.bukkit.scheduler.BukkitScheduler;
 
+import java.io.IOException;
 import java.util.List;
 import java.util.PriorityQueue;
 import java.util.Queue;
@@ -94,7 +97,9 @@ public final class PermissionSigns extends JavaPlugin {
         Stream<SignCreationRequest> matchingRequests = signCreationRequests.stream().filter(
                 (item) -> item.getPlayer().getUniqueId().equals(uuid));
         List<SignCreationRequest> requestList = matchingRequests.toList();
-        signCreationRequests.remove(requestList.get(0));
+        if (requestList.size() > 0) {
+            signCreationRequests.remove(requestList.get(0));
+        }
     }
 
     @Override
@@ -153,11 +158,13 @@ public final class PermissionSigns extends JavaPlugin {
         } else {
             throw new IllegalStateException("[PermissionSigns] Error: Vault could not be loaded");
         }
+        getServer().getPluginManager().registerEvents(new SignListener(), this);
 
         Translator.loadLanguages("en");
         registerCommands();
         BukkitScheduler scheduler = Bukkit.getScheduler();
         scheduler.runTaskTimer(this, new SignCreationRequestTimeoutThread(signCreationRequests), 0L, 100L);
+        SignManager.loadSigns();
     }
 
     /**
@@ -173,7 +180,11 @@ public final class PermissionSigns extends JavaPlugin {
 
     @Override
     public void onDisable() {
-        // Plugin shutdown logic
+        try {
+            SignManager.saveSigns();
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
     }
 
 }