Add installation instructions for conda (#18)

Author: pmeier

README.md

@@ -12,12 +12,18 @@ Some testcases in the PyTorch test suite are automatically generated when a modu
 
 ## How do I install it?
 
-Installing `pytest-pytorch` is as easy as 
+You can install `pytest-pytorch` with `pip`
 
-```
+```shell
 $ pip install pytest-pytorch
 ```
 
+or with `conda`:
+
+```shell
+$ conda install -c conda-forge pytest-pytorch
+```
+
 ## How do I use it?
 
 With `pytest-pytorch` installed you can select test cases and tests as if the instantiation for different devices was performed by [`@pytest.mark.parametrize`](https://docs.pytest.org/en/stable/example/parametrize.html#different-options-for-test-ids):