Merge pull request #1 from borglab/feature/readme

add install instruction

Author: ProfFan

README.md

@@ -1,4 +1,27 @@
 # gtsam-project-python
+
 Project template using GTSAM + python wrapping
 
-Please refer to the [tutorial](TUTORIAL.md) to get started.
+## PREREQUISITES
+
+- Python 3.6+ is required, since we support these versions.
+- Make the following changes to `GTSAM`:
+
+  - Set the CMake flag `GTSAM_INSTALL_CYTHON_TOOLBOX` to `ON` to enable building the cython wrapper.
+  - Set the CMake flag `GTSAM_PYTHON_VERSION` to `3`, otherwise the default interpreter will be used.
+  - You can do this on the command line as follows:
+
+    ```sh
+    cmake -GTSAM_INSTALL_CYTHON_TOOLBOX=ON -DGTSAM_PYTHON_VERSION=3 ..
+    ```
+
+## INSTALL
+
+- In the `example` directory, create the `build` directory and `cd` into it.
+- Run `cmake ..`.
+- Run `make`, and the wrapped module will be installed to a `cython` directory.
+- Navigate to the `cython` directory and run `python setup.py install`.
+
+## DOCUMENTATION
+
+For more detailed information, please refer to the [tutorial](TUTORIAL.md).