Fix docker build #17

This change should fix #17 after adding an empty `frontend/public/index.html`

Dockerfile

@@ -1,8 +1,8 @@
-FROM alpine:3.11
+FROM alpine:3.12
 
 ENV URL=http://localhost:5000
 
-ARG build_deps="go make dep"
+ARG build_deps="go make dep git"
 ARG runtime_deps="dumb-init"
 ARG user_id=1000
 
@@ -13,7 +13,7 @@ RUN apk update && \
     adduser -D -H -h / -u $user_id tty-server && \
     cd /go/src/github.com/elisescu/tty-server && \
     GOPATH=/go dep ensure && \
-    GOPATH=/go make all && \
+    GOPATH=/go PATH=$GOPATH/bin:$PATH make all && \
     cp tty-server /usr/bin/ && \
     rm -r /go && \
     apk del $build_deps