Refactor to remove slices and environments, replace with instances.

app/Models/Application.php

@@ -6,6 +6,8 @@ use App\Enums\RepositoryType;
 use Illuminate\Database\Eloquent\Model;
 use Illuminate\Database\Eloquent\Relations\BelongsTo;
 use Illuminate\Database\Eloquent\Relations\HasMany;
+use Illuminate\Database\Eloquent\Relations\HasManyThrough;
+use Illuminate\Database\Eloquent\Relations\MorphMany;
 
 class Application extends Model
 {
@@ -23,8 +25,18 @@ class Application extends Model
         return $this->belongsTo(Organisation::class);
     }
 
-    public function environments(): HasMany
+    public function instances(): HasMany
     {
-        return $this->hasMany(Environment::class);
+        return $this->hasMany(Instance::class);
+    }
+
+    public function servers(): HasManyThrough
+    {
+        return $this->hasManyThrough(Server::class, Instance::class);
+    }
+
+    public function deployments(): MorphMany
+    {
+        return $this->morphMany(Deployment::class, 'target');
     }
 }