Separate github contributor list from preface

Allow easier translation of preface without including the contributor list, and make additions to contributors easier

github_contributors.asciidoc

@@ -0,0 +1,40 @@
+
+* 8go (@8go)
+* Aaqil Aziz (@batmanscode)
+* Alexander Gnip (@quantumcthulhu)
+* Alpha Q. Smith (@alpha_github_id)
+* Brian L. McMichael (@brianmcmichael)
+* Daniel Gockel (@dancodery)
+* Darius E. Parvin (@DariusParvin)
+* Doru Muntean (@chriton)
+* Eduardo Lima III (@elima-iii)
+* Emilio Norrmann (@enorrmann)
+* Francisco Calderón (@grunch)
+* Francisco Requena (@FrankyFFV)
+* François Degros (@fdegros)
+* Giovanni Zotta (@GiovanniZotta)
+* Gustavo Silva (@GustavoRSSilva)
+* Haoyu Lin (@HAOYUatHZ)
+* Hatim Boufnichel (@boufni95)
+* Imran Lorgat (@ImranLorgat)
+* John Davies (@tigeryant)
+* Julien Wendling (@trigger67)
+* Kory Newton (@korynewton)
+* Lawrence Webber (@lwebbz)
+* Luigi (@gin)
+* Maximilian Karasz (@mknoszlig)
+* Omega X. Last (@omega_github_id)
+* Patrick Lemke (@PatrickLemke)
+* Paul Wackerow (@wackerow)
+* René Köhnke (@rene78)
+* Ricardo Marques (@RicardoM17)
+* Sebastian Falbesoner (@theStack)
+* Sergei Tikhomirov (@s-tikhomirov)
+* Severin Alexander Bühler (@SeverinAlexB)
+* Simone Bovi (@SimoneBovi)
+* Srijan Bhushan (@srijanb)
+* Taylor Masterson (@tjmasterson)
+* Guy Thayakorn (@saguywalker)
+* Umar Bolatov (@bolatovumar)
+* Warren Wan (@wlwanpan)
+* Dapeng Li (@luislee818)

preface.asciidoc

@@ -174,45 +174,7 @@ Many contributors offered comments, corrections, and additions to the book as it
 
 Following is an alphabetically sorted list of all the GitHub contributors, including their GitHub IDs in parentheses:
 
-* 8go (@8go)
-* Aaqil Aziz (@batmanscode)
-* Alexander Gnip (@quantumcthulhu)
-* Alpha Q. Smith (@alpha_github_id)
-* Brian L. McMichael (@brianmcmichael)
-* Daniel Gockel (@dancodery)
-* Darius E. Parvin (@DariusParvin)
-* Doru Muntean (@chriton)
-* Eduardo Lima III (@elima-iii)
-* Emilio Norrmann (@enorrmann)
-* Francisco Calderón (@grunch)
-* Francisco Requena (@FrankyFFV)
-* François Degros (@fdegros)
-* Giovanni Zotta (@GiovanniZotta)
-* Gustavo Silva (@GustavoRSSilva)
-* Haoyu Lin (@HAOYUatHZ)
-* Hatim Boufnichel (@boufni95)
-* Imran Lorgat (@ImranLorgat)
-* John Davies (@tigeryant)
-* Julien Wendling (@trigger67)
-* Kory Newton (@korynewton)
-* Lawrence Webber (@lwebbz)
-* Luigi (@gin)
-* Maximilian Karasz (@mknoszlig)
-* Omega X. Last (@omega_github_id)
-* Patrick Lemke (@PatrickLemke)
-* Paul Wackerow (@wackerow)
-* René Köhnke (@rene78)
-* Ricardo Marques (@RicardoM17)
-* Sebastian Falbesoner (@theStack)
-* Sergei Tikhomirov (@s-tikhomirov)
-* Severin Alexander Bühler (@SeverinAlexB)
-* Simone Bovi (@SimoneBovi)
-* Srijan Bhushan (@srijanb)
-* Taylor Masterson (@tjmasterson)
-* Guy Thayakorn (@saguywalker)
-* Umar Bolatov (@bolatovumar)
-* Warren Wan (@wlwanpan)
-* Dapeng Li (@luislee818)
+include::github_contributors.asciidoc[]
 
 Without the help offered by everyone listed above, this book would not have been possible. Your contributions demonstrate the power of open source and open culture, and we are eternally grateful for your help.