fix assignment and adding IfStatement

src/AST/AssignmentExpression.cpp

@@ -1,7 +1,7 @@
 #include "AST/AssignmentExpression.h"
 #include "AST/ASTVisitor.h"
 
-AssignmentExpression::AssignmentExpression(std::string id, Expression *expr)
+AssignmentExpression::AssignmentExpression(std::string id, Expression *expr) : id_(id),expr_(expr)
 {
     //
 }