Confusing description in extracting the archive (linux)

The current instructions tell you to either use a context menu or the CLI to extract the downloaded archive:

> * If you’re using a graphic interface (e.g., GNOME or Unity on Ubuntu): go to your downloads directory, right click on the downloaded file and select Extract Here.
> * If you’re using the command line (use the right archive file name for your architecture):
> ```
> tar -xf exercism-linux-64bit.tgz
> ```

On the following page then `mv exercism ~/bin/exercism` is done without specifying from where.

Often users run that command from the `~/Download` folder, while some graphical systems will create an extra folder `exercism` during unpacking.

This often leads to users ending up having the exercism binary in `~/bin/exercism/exercism` and therefore `~/bin/exercism` will fail with "is a directory".

I suggest to either exactly specify where the user is expected to be when copying the binary to the designated location, or to strictly remove the references to the GUI and even download through `wget`/`curl`.