updated readme, and fixed linux compilation

src/file_reader.cpp

@@ -1,3 +1,4 @@
+#include <vector>
 #include "../include/file_reader.hpp"
 
 void FileReader::refill_buffer()

src/file_writer.cpp

@@ -1,3 +1,4 @@
+#include <vector>
 #include "../include/file_writer.hpp"
 
 void FileWriter::write_buffer()

src/merge_sorter.cpp

@@ -1,3 +1,5 @@
+#include <algorithm>
+#include <queue>
 #include "../include/merge_sorter.hpp"
 
 std::span<Record> MergeSorter::get_chunk_span(size_t chunk_index)