title: error: An entity must have at least 1 field annotated with @PrimaryKey
body: <p>I am new to using room persistence and I have this error whenever I try running my code. It shows no error when editing but I get build error on gradle. It failed me that I had to copy paste codes but none seemed to work. The error is below </p>
  
  <pre><code>error: An entity must have at least 1 field annotated with @PrimaryKey
  </code></pre>
  
  <p>How do I work it out?
  My code is below;</p>
  
  <pre><code> package com.revosleap.dummy.DatabaseMov;
  
  import android.arch.persistence.room.ColumnInfo;
  import android.arch.persistence.room.Entity;
  import android.arch.persistence.room.Ignore;
  import android.arch.persistence.room.PrimaryKey;
  
  @Entity
  
  public class TodoListItem {
      @Ignore
      @PrimaryKey(autoGenerate = true)
       private int id;
  
      @ColumnInfo(name = "time")
      private String time;
  
      @ColumnInfo(name="title")
      private String title;
  
      public TodoListItem(){
  
      }
  
      public TodoListItem(String time, String title) {
          this.time = time;
          this.title = title;
      }
  
      public String getTime() {
          return time;
      }
  
      public void setTime(String time) {
          this.time = time;
      }
  
      public String getTitle() {
          return title;
      }
  
      public void setTitle(String title) {
          this.title = title;
      }
  
      public int getId() {
          return id;
      }
  
      public void setId(int id) {
          this.id = id;
      }
  }
  </code></pre>