title: Unable to find a specification for `Firebase
body: <p>I got problem with the installation of Firebase on Xcode for a swift application.</p>
  
  <p>I got this error:</p>
  
  <blockquote>
    <p>pod Unable to find a specification for <code>Firebase (&gt;= 2.5.0)</code></p>
  </blockquote>
  
  <p>My Podfile is this one:</p>
  
  <pre><code># Uncomment this line to define a global platform for your project
  # platform :ios, '8.0'
  # Uncomment this line if you're using Swift
  use_frameworks!
  
  pod 'Firebase', '&gt;= 2.5.0'
  target 'banana' do
  
  end
  
  target 'bananaTests' do
  
  end
  
  target 'bananaUITests' do
  
  end
  </code></pre>
  
  <p>I don't know why because I followed each step of the tutorial from Firebase.</p>