message: Added Downloads badge
diff: @@ -31,6 +31,8 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  [![C++17](https://img.shields.io/badge/C%2B%2B-17-blue.svg)](https://isocpp.org/std/the-standard )
  [![Codacy Badge](https://api.codacy.com/project/badge/Grade/db646376a4014c3788c7224e670fe451)](https://app.codacy.com/manual/hosseinmoein/DataFrame?utm_source=github.com&utm_medium=referral&utm_content=hosseinmoein/DataFrame&utm_campaign=Badge_Grade_Dashboard)
  [![Binder](https://mybinder.org/badge_logo.svg)](https://mybinder.org/v2/gh/hosseinmoein/DataFrame/master)
  +[![Github All Releases](https://img.shields.io/github/downloads/hosseinmoein/DataFrame/total.svg)]()
  +
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