Add user input with DTMF example

Author: mheap

voice/user-input-dtmf-slim/composer.json

@@ -0,0 +1,8 @@
+{
+ "require": {
+ "slim/slim": "^3.8"
+ },
+ "require-dev": {
+ "squizlabs/php_codesniffer": "^3.1"
+ }
+}