Document emojis

README.md

@@ -4,6 +4,12 @@ General-purpose text classifier in Python
 
 GPTC provides both a CLI tool and a Python library.
 
+## Installation
+
+    pip install gptc[emoji] # handles emojis! (see section "Emoji")
+    # Or, if you don't need emoji support,
+    pip install gptc # no dependencies!
+
 ## CLI Tool
 
 ### Classifying text
@@ -72,6 +78,12 @@ reduced to the one used when compiling the model.
 Models compiled with older versions of GPTC which did not support ngrams are
 handled the same way as models compiled with `max_ngram_length=1`.
 
+## Emoji
+
+If the [`emoji`](https://pypi.org/project/emoji/) package is installed, GPTC
+will automatically handle emojis the same way as words. If it is not installed,
+GPTC will still work but will ignore emojis.
+
 ## Model format
 
 This section explains the raw model format, which is how you should create and