title: Altering SQLite column type and adding PK constraint
body: <p>How to change the type of a column in a SQLite table?</p>
  
  <p>I've got:</p>
  
  <pre><code>    CREATE TABLE table(
          id INTEGER,
          salt TEXT NOT NULL UNIQUE,
          step INT,
          insert_date TIMESTAMP
      );
  </code></pre>
  
  <p>I'd like to change <code>salt</code>'s type to just <code>TEXT</code> and id's type to INTEGER PRIMARY KEY.</p>