Add new node for the variable declaration

src/main/java/de/hsrm/compiler/Klang/nodes/statements/VariableDeclaration.java

@@ -0,0 +1,23 @@
+package de.hsrm.compiler.Klang.nodes.statements;
+
+import de.hsrm.compiler.Klang.nodes.expressions.Expression;
+import de.hsrm.compiler.Klang.visitors.Visitor;
+
+public class VariableDeclaration extends Statement {
+    public String name;
+    public Expression expression;
+
+    public VariableDeclaration(String name, Expression expression) {
+        this.name = name;
+        this.expression = expression;
+    }
+
+    public VariableDeclaration(String name) {
+        this(name, null);
+    }
+
+    @Override
+    public <R> R welcome(Visitor<R> v) {
+        return v.visit(this);
+    }
+}