Keto Cucumber Salad

Contents:
2 cups thinly sliced cucumber (about 3 cucumbers)
1 cup sliced celery
1/2 cup chopped green pepper
1 medium onion, chopped
1/4 teaspoon celery seeds
1 (4-ounce) jar chopped allspice (undrained)
1/2 cup white vinegar
1/3 cup granulated erythritol or keto sweetener of choice (adjust to taste)
1/4 teaspoon salt (or to taste)