Issue #57: Update contributors list (#58)

* Add additional contributors and acknowledgements.

Author: AerialMantis

affinity/cpp-20/d0796r2.md

@@ -6,7 +6,7 @@
 
 **Authors: Gordon Brown, Ruyman Reyes, Michael Wong, H. Carter Edwards, Thomas Rodgers, Mark Hoemmen**
 
-**Contributors: Patrice Roy, Carl Cook, Jeff Hammond**
+**Contributors: Patrice Roy, Carl Cook, Jeff Hammond, Hartmut Kaiser, Christian Trott, Paul Blinzer, Alex Voicu**
 
 **Emails: gordon@codeplay.com, ruyman@codeplay.com, michael@codeplay.com, hedwards@nvidia.com, rodgert@twrodgers.com, mhoemme@sandia.gov**
 
@@ -576,6 +576,10 @@ The current proposal requires that all `execution_resource`s are initialized bef
 |------------|
 | Should we support dynamically adding and removing `execution_resource`s at run time? |
 
+# Acknowledgements
+
+Thanks to Christopher Di Bella, Toomas Remmelg and Morris Hafner for their reviews and suggestions.
+
 # References
 
 [p0687r0]: http://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p0687r0.pdf