Tip: Docker unable to copy bin\Debug folder to the target image.

Recently I have been playing with the Docker whereby i was trying to copy my simple Visual Studio project exe from bin\Debug to the target image location. My Docker file looks like this:

FROM microsoft/nanoserver
WORKDIR c:/
RUN DIR
COPY /bin/Debug/ /ConsoleApp2/
RUN DIR C:\ConsoleApp2
CMD ["C:\\ConsoleApp2\\ConsoleApp2.exe","",""] 

However when i executed the command docker build -t consoleapp2:dev . an error showed up: GetFileAttributesEx bin\\Debug\: The system cannot find the path specified. saying that the folder could not be found when actually the folder was there. So I digged into the .dockerignore file that accompanies the Dockerfile when I added it through Visual Studio. Inside the file there's a bunch of patterns that filter out related files or directories, so i removed everything from that file and run the Docker build command, the next thing you know it was a successful run.

* (Culprit)
!obj\Docker\publish\*
!obj\Docker\empty\

Only obj folder get copied over.
A successful run.

Sending build context to Docker daemon 123.9 kB
Step 1/6 : FROM microsoft/nanoserver
 ---> 4a8212a9c691
Step 2/6 : WORKDIR c:/
 ---> Using cache
 ---> ebcfa5b95aa7
Step 3/6 : RUN DIR
 ---> Using cache
 ---> 6dfa39dc1b7b
Step 4/6 : COPY /bin/Debug/ /ConsoleApp2/
 ---> fb65c840b3eb
Removing intermediate container 8eb904bad33a