title: <FirebaseDatabase/FirebaseDatabase.h> is not found (lexcial or preprocessor issuses)
body: <p><a href="https://i.stack.imgur.com/qAWHm.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/qAWHm.png" alt="enter image description here"></a><a href="https://i.stack.imgur.com/7XDWf.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/7XDWf.png" alt="enter image description here"></a>friends, i install the pod file called 
  SwiftCountrySelector for selecting countries but after pod installation i got the error called FirebaseDatabase/FirebaseDatabase.h is not found.help me friends</p>
  
  <p>my pod file is above</p>