associationsFor(modelName) {
    let modelClass = this.modelClassFor(modelName);

    return Object.assign(
      {},
      modelClass.belongsToAssociations,
      modelClass.hasManyAssociations
    );
  }
Returns an object containing the associations registered for the model of the given _modelName_.

    For example, given this configuration
    
    ```js
    import { createServer, Model, hasMany, belongsTo } from 'miragejs'

    let server = createServer({
      models: {
        user: Model,
        article: Model.extend({
          fineAuthor: belongsTo("user"),
          comments: hasMany()
        }),
        comment: Model
      }
    })
    ```

    each of the following would return empty objects

    ```js
    server.schema.associationsFor('user')
    // {}
    server.schema.associationsFor('comment')
    // {}
    ```

    but the associations for the `article` would return

    ```js
    server.schema.associationsFor('article')

    // {
    //   fineAuthor: BelongsToAssociation,
    //   comments: HasManyAssociation
    // }
    ```

    Check out the docs on the Association class to see what fields are available for each association.

    @method associationsFor
    @param {String} modelName
    @return {Object}
    @public