title: Sign user in ONLY if email and password are correct?
body: <p>I have a form that when you click submit it goes to the path /signin no matter what, even if you don't enter anything into the form. However I want it to check if there is a user with the email entered and if their password is correct before going to /signin. If the email is not known or the password is not correct then I want it to display an error (and stay on the log in page). I've been trying to get this to work but I'm not sure how to do it. Does anyone know how to do this? This is the code I have so far:</p>
  
  <p>html:</p>
  
  <pre><code>&lt;div id="topbar"&gt;
    &lt;h1&gt;&lt;strong&gt;chattly&lt;/strong&gt;&lt;/h1&gt;
          {{#unless currentUser}}
              {{&gt; signIn}}
              {{&gt; alert}}
          {{else}}
              {{&gt; signOut}}
          {{/unless}}
      &lt;/div&gt;
  </code></pre>
  
  <p>javascript:</p>
  
  <pre><code>// Sign In Template
  Template.signIn.events({
      'submit #signInForm': function(e, t) {
          e.preventDefault();
  
          var signInForm = $(e.currentTarget),
              email = trimInput(signInForm.find('.email').val().toLowerCase()),
              password = signInForm.find('.password').val();
  
          if (isNotEmpty(email) &amp;&amp; isEmail(email) &amp;&amp; isNotEmpty(password) &amp;&amp; isValidPassword(password)) {
              Meteor.loginWithPassword(email, password, function(err) {
                  if (err) {
                      Session.set('alert', 'We\'re sorry but these credentials are not valid.');
                  } else {
                      Sesson.set('alert', 'Welcome back New Meteorite!');
                  }
              });
          }
          return false;
      },
  });
  </code></pre>