wrote steps to install docker in readme and wrote a dockerfile for nginx not tested

srcs/requirements/test/Dockerfile

@@ -12,3 +12,41 @@ FROM scratch
 COPY tools/hello /
 CMD [ "/hello" ]
 
+## working
+#FROM scratch
+#WORKDIR /
+#COPY hello /
+#CMD [ "/hello" ]
+
+## working, when WORKDIR is absent, it's default is set to "/"
+#FROM scratch
+#COPY hello /
+#CMD [ "/hello" ]
+
+## not working, when CMD execute in shell form, instead of exec form []
+#FROM scratch
+#COPY hello /
+#CMD /hello
+
+## not working, because c executable need library <unistd.h>
+#FROM scratch
+#COPY hello_c /
+#CMD [ "/hello_c" ]
+
+## not working, when executable is copied to ".", because WORKDIR value is not "." but "/" since we gave it a relativ path so it was build in top of the implicit absolut path "/"
+#FROM scratch
+#WORKDIR .
+#COPY hello .
+#CMD [ "hello" ]
+
+## not working, when WORKDIR is set to the present directory and executable is not copied, because the workdir is not the present directory but a directory in the file system of docker : executable need to be copied there to function
+#FROM scratch
+#WORKDIR /home/simplonco/Desktop/42/14_inception/inception/srcs/requirements/mariadb
+#CMD [ "hello" ]
+
+## working, because "hello" is copied to "/" and execute from "/"
+#FROM scratch
+#WORKDIR .
+#COPY hello /
+#CMD [ "/hello" ]
+