Add Gitember Git GUI client

Author: iazarny

data/guis/gitember.yml

@@ -0,0 +1,13 @@
+---
+name: "Gitember"
+project_url: "https://gitember.org/"
+image_tag: "images/guis/gitember@2x.png"
+platforms:
+  - "Windows"
+  - "Mac"
+  - "Linux"
+price: "Free"
+license: "GNU"
+trend_name: "Gitember"
+order: 61
+---