Can you figure out this secret emoji cipher?

      
Know what I’m saying? This is a cipher and it comes from a neat little project by Mozilla called Codemoji.
“Decipher” is a word we use often enough, but might not understand where it comes from. A cipher is like a secret code, where each letter or symbol stands for a different letter. Ciphers are the building blocks of encryption, a topic near to Mozilla’s heart (you can check out the browser’s video series on the topic here).
“It’s part of our cross-organization effort to educate about encryption,” explained Aure Moser of the Mozilla Science Lab (which, btw, has a fellowship you should check out).
With Codemoji, you write a sentence or phrase, pick an emoji through which to translate it, and out comes your message, in emoji cipher.
So my message, “Hi, readers :)” translated through the Codemoji cipher algorithm becomes:       
Try it out for yourself here.