add error function, README and CI

README.md

@@ -0,0 +1,35 @@
+## libragephoto
+Open Source RAGE Photo Parser for GTA V
+
+- Read RAGE Photos error free and correct
+- Support for metadata stored in RAGE Photos
+- Export RAGE Photos to jpeg with ragephoto-extract
+- High Efficient and Simple C++ API
+
+#### Build libragephoto & ragephoto-extract
+
+```bash
+git clone https://gitlab.com/Syping/libragephoto && cd libragephoto
+mkdir -p build && cd build
+cmake ../
+make -j $(nproc --all)
+sudo make install
+```
+
+#### How to Use libragephoto
+
+```cpp
+RagePhoto ragePhoto;
+bool loaded = ragePhoto.load(data, size);
+const char* photoData = ragePhoto.photoData();
+uint32_t photoSize = ragePhoto.photoSize();
+std::string json = ragePhoto.json();
+std::string title = ragePhoto.title();
+RagePhoto::Error error = ragePhoto.error();
+```
+
+#### How to Use ragephoto-extract
+
+```bash
+ragephoto-extract PGTA5123456789 photo.jpg
+```