Exclude the dummy courses from surefire.

Author: Aleksi Salmela

pom.xml

@@ -89,6 +89,11 @@
                 <groupId>org.apache.maven.plugins</groupId>
                 <artifactId>maven-surefire-plugin</artifactId>
                 <version>2.18.1</version>
+                <configuration>
+                    <excludes>
+                        <exclude>**/dummy-courses/**/*</exclude>
+                    </excludes>
+                </configuration>
             </plugin>
             <plugin>
                 <groupId>org.apache.maven.plugins</groupId>