docs: add README

Author: Yimura

README.md

@@ -0,0 +1,70 @@
+# AsyncLogger
+
+## How to use
+
+Very simple example application showing how to implement it.
+
+main.cpp
+```cpp
+#include "Logger.hpp"
+#include <filesystem>
+#include <iostream>
+
+using namespace base;
+
+void COUT_LOG(LogMessagePtr msg)
+{
+    const auto& location = msg->Location();
+    const auto file = std::filesystem::path(msg->Location().file_name()).filename().string();
+
+    std::cout << "[" << file << ":" << location.line() << "] " << msg->Message();
+}
+
+int main()
+{
+    Logger::Init();
+    Logger::AddSink(COUT_LOG);
+
+    LOG(INFO) << "Test " << 1 << 2 << 3 << " some float (" << 3.5f << ")";
+
+    Logger::Destroy();
+
+    return 0;
+}
+```
+Logs the following output:
+```
+[main.cpp:20] Test 123 some float (3.5)
+```
+
+CMakeLists.txt
+```cmake
+cmake_minimum_required(VERSION 3.20)
+set(CMAKE_CXX_STANDARD 20 GLOBAL)
+
+project(my_app LANGUAGES CXX VERSION 0.0.1)
+
+add_subdirectory(AsyncLogger)
+add_executable(${PROJECT_NAME} src/main.cpp)
+target_link_libraries(${PROJECT_NAME} AsyncLogger)
+```
+
+CMakeLists.txt using FetchContent
+```cmake
+cmake_minimum_required(VERSION 3.20)
+set(CMAKE_CXX_STANDARD 20 GLOBAL)
+
+project(my_app LANGUAGES CXX VERSION 0.0.1)
+
+include(FetchContent)
+FetchContent_Declare(
+    AsyncLogger
+    GIT_REPOSITORY https://github.com/Yimura/AsyncLogger.git
+    GIT_TAG master
+    GIT_PROGRESS TRUE
+)
+FetchContent_MakeAvailable(AsyncLogger)
+
+add_executable(${PROJECT_NAME} src/main.cpp)
+target_link_libraries(${PROJECT_NAME} AsyncLogger)
+```