Add gravity.

index.html

@@ -25,6 +25,11 @@ projects:
           incomplete:  yes
           description: An emulator for the <a href="https://en.wikipedia.org/wiki/Sega_Game_Gear">Sega Game Gear</a>, with an included <a href="https://en.wikipedia.org/wiki/Zilog_Z80">Z80</a> assembler/disassembler
     others:
+        - name:        gravity
+          repo:        EnacheB/Gravity
+          langs:       C++
+          started:     November 2015
+          description: A multiplayer top-down orbital space shooter
         - name:        tfdclerk
           langs:       JavaScript
           started:     August 2015