Dockerfile: Change watcher version

Author: canthefason

Dockerfile

@@ -16,9 +16,14 @@ ENV GO_VERSION 1.7
 
 RUN curl -s -L https://raw.githubusercontent.com/moovweb/gvm/master/binscripts/gvm-installer | bash
 
-RUN . /root/.gvm/scripts/gvm && gvm install go1.4 && gvm use go1.4 && gvm install go1.5 && gvm install go1.6 && gvm install go1.7
-
-ENV WATCHER_VERSION 0.2.3
+RUN . /root/.gvm/scripts/gvm && \
+      gvm install go1.4 && \
+      gvm use go1.4 && \
+      gvm install go1.5 && \
+      gvm install go1.6 && \
+      gvm install go1.7
+
+ENV WATCHER_VERSION 0.2.4
 
 ADD https://github.com/canthefason/go-watcher/releases/download/v${WATCHER_VERSION}/watcher-${WATCHER_VERSION}-linux-amd64 /root/.gvm/bin/watcher