text: import {Schema, model} from 'mongoose';
  import uniqueValidator from 'mongoose-unique-validator';
  
  const SoilSchema = new Schema({
    name: {type: String, required: true, unique: true},
    trees: [{type: Schema.Types.ObjectId, ref: 'Tree'}]
  });
  
  SoilSchema.plugin(uniqueValidator);
  export default model('Soil', SoilSchema);
  