Updating graph

* Implemented MatrixGraph
* Changed save/load logics (test not passing)

build.gradle

@@ -14,13 +14,9 @@ test {
     useJUnitPlatform()
 }
 
-sourceSets {
-    main {
-        java {
-            srcDirs "src"
-            srcDirs "test"
-        }
-    }
+sourceSets.main.java {
+    srcDirs "src"
+    srcDirs "test"
 }
 
 repositories {
@@ -28,8 +24,9 @@ repositories {
 }
 
 dependencies {
-	compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5'
+    implementation 'org.junit.jupiter:junit-jupiter:5.5.2'
+    compile group: 'com.google.code.gson', name: 'gson', version: '2.8.5'
 	
 	/*compile group: 'commons-collections', name: 'commons-collections', version: '3.2'*/
-	testCompile 'junit:junit:4.4'
+	testCompile 'junit:junit:5.5.2'
 }