title: What is the use of JdbcApprovalStore(ApprovalStore) in spring-security-oauth?
body: <p>I am using <code>JWTTOkenStore</code> in spring-security-oauth. </p>
  
  <p>The issue I am facing is I want to add support of revoking JWT token.
  I know there are other options to handle this but I am looking for this option.
  I found that we can use <code>org.springframework.security.oauth2.provider.approval.JdbcApprovalStore</code> for the same. Is my understanding correct? I really searched on internet for some example, but I did not find any.</p>
  
  <pre><code>    /**
       * ApprovalStore to be used to validate and restrict refresh tokens.
       * 
       * @param approvalStore the approvalStore to set
       */
      public void setApprovalStore(ApprovalStore approvalStore) {
          this.approvalStore = approvalStore;
      }
  </code></pre>
  
  <p>Can someone please explain me briefly what is the use <code>JdbcApprovalStore</code> with <code>JWTTokenStore</code>?</p>