enforce utf-8 encoding

pom.xml

@@ -3,6 +3,9 @@
          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
     <modelVersion>4.0.0</modelVersion>
+    <properties>
+        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
+    </properties>
 
     <groupId>edu.unl.cse.csce361.socket_chat</groupId>
     <artifactId>SocketChat</artifactId>