This is a very small issue. While Feliwir was explaining to me his attempt to add alpha it seemed like he missed the Blend Mode setting which I have circled in the screenshot.
Here is an example of the shader material nodes and settings that I use to display alpha in Blender. The default render engine in Blender 2.8 is Eeevee and this setting is only available for Eevee.

I recommend using either the Alpha Clip or Alpha Blend setting.
This is a very small issue. While Feliwir was explaining to me his attempt to add alpha it seemed like he missed the Blend Mode setting which I have circled in the screenshot.
Here is an example of the shader material nodes and settings that I use to display alpha in Blender. The default render engine in Blender 2.8 is Eeevee and this setting is only available for Eevee.
I recommend using either the Alpha Clip or Alpha Blend setting.