Add Sigma-One to credits.

Cervator · Cervator · commit 1c2da1d37a26 · 2017-05-07T16:49:08.000-04:00
diff --git a/README.markdown b/README.markdown
@@ -121,6 +121,7 @@ Contributors
 * [JGelfand](https://github.com/JGelfand)
 * [AvaLanCS](https://github.com/Avalancs)
 * [scirelli](https://github.com/scirelli)
+* [Sigma-One](https://github.com/Sigma-One)
 
 ... and your name here? :-) More coming!
 
diff --git a/main/src/org/destinationsol/menu/CreditsScreen.java b/main/src/org/destinationsol/menu/CreditsScreen.java
@@ -73,7 +73,8 @@ public CreditsScreen(float r, GameOptions gameOptions) {
         "theotherjay, LinusVanElswijk",
         "SimonC4, grauerkoala, rzats",
         "LadySerenaKitty, askneller",
-        "JGelfand, AvaLanCS. scirelli"
+        "JGelfand, AvaLanCS. scirelli",
+        "Sigma-One"
       },
       {
         "Soundtrack by NeonInsect"
