Add entry about recommended CUDA version and pyenv

Signed-off-by: Adam Wawrzyński <adam.wawrzynski@reasonfieldlab.com>

README.md

@@ -4,6 +4,11 @@
 
 The project was tested using Python version `3.8`.
 
+## CUDA
+
+Recommended version of CUDA is `10.2` as it is supported since version
+`1.5.0` of `torch`.
+
 ## Poetry
 
 To separate runtime environments for different services and repositories, it is
@@ -34,6 +39,34 @@ Once all the steps have been completed, the environment is ready to go.
 Virtual environment by default will be created with name `.venv` inside
 project directory.
 
+## pyenv
+
+`pyenv` is a tool used to manage multiple version of Python. To install
+this package follow instructions on project repository page:
+https://github.com/pyenv/pyenv#installation. After installation You can
+install desired Python version, e.g. `3.8.16`:
+```bash
+pyenv install 3.8.16
+```
+
+The next step is required to be able to use desired version of Python with
+`poetry`. To activate specific version of Python interpreter execute command:
+```bash
+pyenv local 3.8.16 # or `pyenv global 3.8.16`
+```
+
+Inside repository with `poetry` You can select specific version of Python
+interpreter with command:
+```bash
+poetry env use 3.8.16
+```
+
+After changing interpreter version You have to once again install all
+dependencies:
+```bash
+poetry install
+```
+
 ### Installation errors
 
 If You encounter errors during dependencies installation You can disable