Added server config values to check user name minimal and maximal length and allowed chars for user name. Set to 3-14 length and [^a-z0-9_] chars (ignoring case) .

Mage.Server/src/main/java/mage/server/util/ConfigSettings.java

@@ -83,6 +83,18 @@ public class ConfigSettings {
         return config.getServer().getMaxSecondsIdle().intValue();
     }
 
+    public int getMinUserNameLength() {
+        return config.getServer().getMinUserNameLength().intValue();
+    }
+
+    public int getMaxUserNameLength() {
+        return config.getServer().getMaxUserNameLength().intValue();
+    }
+
+    public String getUserNamePattern() {
+        return config.getServer().getUserNamePattern();
+    }
+
     public List<Plugin> getPlayerTypes() {
         return config.getPlayerTypes().getPlayerType();
     }