add git to docker image

Author: Joe Cardella

src/Dockerfile

@@ -1,6 +1,6 @@
 FROM alpine:latest
 ARG DIFFY_VERSION=0.1.22
 RUN apk update && \
-    apk add bash openssl php php-openssl php-phar php-iconv && \
+    apk add bash git openssl php php-openssl php-phar php-iconv && \
     wget -O /usr/local/bin/diffy https://github.com/DiffyWebsite/diffy-cli/releases/download/${DIFFY_VERSION}/diffy.phar && \
     chmod u+x /usr/local/bin/diffy