making the "jar" target actually work, verified libs in jar

.gitignore

@@ -1 +1,2 @@
 *.class
+dist

build.xml

@@ -13,6 +13,7 @@
 
     <target name="jar" depends="build"
             description="create Jar from compiled sources">
+        <mkdir dir="dist" />
         <jar destfile="dist/learning-java.jar">
             <fileset dir="obj" includes="**/*.class"/>
         </jar>