More singularization and correct file names.

app/Models/Server.php

@@ -263,7 +263,7 @@ class Server extends Model
      */
     public function variables()
     {
-        return $this->hasMany(ServerVariables::class);
+        return $this->hasMany(ServerVariable::class);
     }
 
     /**

app/Models/ServerVariable.php

@@ -26,7 +26,7 @@ namespace Pterodactyl\Models;
 
 use Illuminate\Database\Eloquent\Model;
 
-class ServerVariables extends Model
+class ServerVariable extends Model
 {
     /**
      * The table associated with the model.

app/Models/ServiceVariable.php

@@ -54,8 +54,8 @@ class ServiceVariable extends Model
          'required' => 'integer',
      ];
 
-    public function serverVariables()
+    public function ServerVariable()
     {
-        return $this->hasMany(ServerVariables::class, 'variable_id');
+        return $this->hasMany(ServerVariable::class, 'variable_id');
     }
 }