Change license to Apache 2.0 and update contributors list (#352)

* Change license to Apache 2.0 and update contributors list

* Update CONTRIBUTORS.md

Co-Authored-By: mattn <mattn.jp@gmail.com>

CONTRIBUTORS.md

@@ -2,27 +2,30 @@
 
 The following contributors have contributed in ways that required knowing how Gorgonia works - essentially forming the "backbone" of expertise
 
-* Xuanyi Chew @chewxy - initial package
-* Ethan Lin @lynic - convolution bug fixes
-* Joe  Kabaka @kabaka0 - masked array functionality
-* Jorge Landivar @docmerlin - tests, bug finding and documentation
-* Dan Kortschak @kortschak - Gonum Graphs
-* Gareth Seneque @jokebroker - Release Czar
-* Matoko Ito @ynqa - tests, documentation and bug finding
-* Naseer Dari @ndari - errors and error handling
-* Olivier Wulveryck - Gonnx  and more
-* Pascal Masschelier @pa-m - Max op
+* Xuanyi Chew (@chewxy) - initial package
+* Ethan Lin (@lynic) - convolution bug fixes
+* Joe Kabaka (@kabaka0) - masked array functionality
+* Jorge Landivar (@docmerlin) - tests, bug finding and documentation
+* Dan Kortschak (@kortschak) - Gonum Graphs
+* Gareth Seneque (@jokebroker) - Release Czar
+* Matoko Ito (@ynqa) - tests, documentation and bug finding
+* Naseer Dari (@ndari) - errors and error handling
+* Olivier Wulveryck (@owulveryck) - Gonnx and more
+* Pascal Masschelier (@pa-m) - Max op
 * Siquus (@siquus) - TensorDot, contraction
 * Tan Chen (@tantanchen) - Bug finding and documentation
 * Geoff Sindel (@durp) - gomod
+* Ben Leitner (@bdleitner)
+* Nabil Servais (@blackrez)
+* Yasuhiro Matsumoto (@mattn)
 
 
 # Contributors 2 #
 
 The following contributors have contributed to the quality of the project
 
 * Andrew Murray | @radarhere
-* Ankit Raj | @aj0t
+* Ankit Raj | @aj07
 * Bart Fokker | @barthr
 * Bradley J Kemp | @bradleyjkemp
 * David Soller | @3ygun
@@ -35,5 +38,10 @@ The following contributors have contributed to the quality of the project
 * Vadim | @trigun117
 * Yuanlin Lian | @alienchow
 * Mathieu Ronse (Logo) | @WeAreBears
+* Vicente Olmedo | @volmedo
+* Ilya Kaznacheev | @ilyakaznacheev
+* Abhimithra Karthikeya | @freakomonk
+* @bezineb5
+* @stock1218
 
-For more contributors, check out the [github contributors page](https://github.com/gorgonia/graphs/contributors)
+For more contributors, check out the [github contributors page](https://github.com/gorgonia/gorgonia/graphs/contributors)