title: How to delete document from firestore using where clause
body: <pre><code>var jobskill_ref = db.collection('job_skills').where('job_id','==',post.job_id);
  jobskill_ref.delete();
  </code></pre>
  
  <p><strong>Error thrown<br/></strong></p>
  
  <blockquote>
    <p>jobskill_ref.delete is not a function</p>
  </blockquote>