bash won't enter to else [duplicate]

This question already has an answer here:

• How do I compare two string variables in an 'if' statement in Bash? 11 answers

I have this code that expects string from the end user:

#!/bin/bash

echo "You are about to deploy the site from STAGING to PRODUCTION, Are you sure? yes/no ";

read continue

if (( "$continue" == "yes" )) ; then
        echo "Yes"
else
        echo "No"
fi

The problem is that the else will never be.

Thanks