docker + linux build fix

.dockerignore

@@ -1 +1,3 @@
 build
+CMakeCache.txt
+ws/CMakeCache.txt

Dockerfile

@@ -44,4 +44,5 @@ RUN ldd /usr/local/bin/ws
 USER app
 WORKDIR /home/app
 
-CMD ["ws"]
+ENTRYPOINT ["ws"]
+CMD ["--help"]

ixwebsocket/IXSocketServer.cpp

@@ -13,6 +13,7 @@
 #include <sstream>
 #include <future>
 #include <string.h>
+#include <assert.h>
 
 namespace ix
 {