Use the direct address to the onboarding guide rather than assuming the...

Use the direct address to the onboarding guide rather than assuming the redirect will actually work...

README.md

@@ -18,7 +18,7 @@ More general information about SWIFT is available on the project
 [webpages](http://www.swiftsim.com).
 
 For information on how to _run_ SWIFT, please consult the onboarding guide
-available [here](http://www.swiftsim.com/onboarding.pdf). This includes
+available [here](https://swift.strw.leidenuniv.nl/onboarding.pdf). This includes
 dependencies, and a few examples to get you going.
 
 We suggest that you use the latest release branch of SWIFT, rather than the

doc/RTD/source/GettingStarted/index.rst

@@ -9,7 +9,7 @@ to get up and running with some examples, and then build your own initial condit
 for running.
 
 Also, you might want to consult our onboarding guide (available at
-http://www.swiftsim.com/onboarding.pdf) if you would like something to print out
+https://swift.strw.leidenuniv.nl/onboarding.pdf) if you would like something to print out
 and keep on your desk.
 
 .. toctree::

doc/onboardingGuide/README.md

 SWIFT Onboarding Guide
 ======================
 
-This is an onboarding guide for SWIFT that can be found on `swiftsim.com/onboarding.pdf`.
+This is an onboarding guide for SWIFT that can be found on `https://swift.strw.leidenuniv.nl/onboarding.pdf`.
 
 You will need the `sphinx` and python package (pip install it), as well as a working
 TeX distribution.

doc/onboardingGuide/source/getting_help.rst

@@ -11,4 +11,4 @@ by creating an issue.
 The code documentation is available on `swiftsim.com/docs <https://swiftsim.com/docs>`_, and
 is also shipped along with the code in the ``docs/RTD`` directory. 
 This onboarding guide is available online as well on 
-`swiftsim.com/onboarding.pdf <http://www.swiftsim.com/onboarding.pdf>`_
+`swiftsim.com/onboarding.pdf <https://swift.strw.leidenuniv.nl/onboarding.pdf>`_