use enum for permissions

src/main/java/me/youhavetrouble/preventstabby/config/PreventStabbyPermission.java

@@ -0,0 +1,26 @@
+package me.youhavetrouble.preventstabby.config;
+
+import org.bukkit.command.CommandSender;
+
+public enum PreventStabbyPermission {
+
+    COMMAND("preventstabby.command"),
+    COMMAND_TOGGLE("preventstabby.command.toggle"),
+    COMMAND_TOGGLE_OTHERS("preventstabby.command.toggle.others"),
+    COMMAND_RELOAD("preventstabby.command.reload");
+
+    private final String permission;
+    PreventStabbyPermission(String permission) {
+        this.permission = permission;
+    }
+
+    public boolean doesCommandSenderHave(CommandSender sender) {
+        return sender.hasPermission(permission);
+    }
+
+    @Override
+    public String toString() {
+        return permission;
+    }
+
+}