changed installation docs accordintly

Author: Takaya Uchida

doc/installation.rst

@@ -7,9 +7,13 @@ The quickest way
 ----------------
 
 xrft is compatible both with Python 2 and 3. The major dependencies are xarray_ and dask_.
-The best way to install them is using Anaconda_.::
+The best way to install them is using Anaconda_::
 
-    $ conda install xarray dask .
+    $ conda install -c conda-forge xarray dask xrft .
+
+It is also possible to install from PyPI_ by::
+
+    $ pip install xrft .
 
 Install xrft from GitHub repo
 -----------------------------
@@ -23,8 +27,9 @@ Developers can track source code changes by::
 
     $ git clone https://github.com/xgcm/xrft.git
     $ cd xrft
-    $ python setup.py build .
+    $ python setup.py develop .
 
 .. _xarray: http://xarray.pydata.org
 .. _dask: http://dask.pydata.org/en/latest/
 .. _Anaconda: https://www.continuum.io/downloads
+.. _PyPI: https://pypi.org/