Add license to 6 books

books/free-programming-books-langs.md

@@ -806,12 +806,12 @@ Books on general-purpose programming that don't focus on a specific language are
 ### Go
 
 * [An Introduction to Programming in Go](https://www.golang-book.com/books/intro) - Caleb Doxsey
-* [Build Web Application with Golang](https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/) - astaxie
+* [Build Web Application with Golang](https://astaxie.gitbooks.io/build-web-application-with-golang/content/en/) - astaxie (CC BY-SA)
 * [Building Web Apps with Go](https://codegangsta.gitbooks.io/building-web-apps-with-go/content/)
 * [Darker Corners of Go](https://rytisbiel.com/2021/03/06/darker-corners-of-go/) - Rytis Bieliunas
 * [Effective Go](https://golang.org/doc/effective_go.html)
-* [Essential Go](https://www.programming-books.io/essential/go/) - Krzysztof Kowalczyk, StackOverflow Contributors
-* [Essentials of Go Programming](https://essentials-of-go-programming.readthedocs.io) - Baiju Muthukadan (HTML)
+* [Essential Go](https://www.programming-books.io/essential/go/) - Krzysztof Kowalczyk, StackOverflow Contributors (CC BY-SA)
+* [Essentials of Go Programming](https://essentials-of-go-programming.readthedocs.io) - Baiju Muthukadan (HTML) (CC BY-SA)
 * [Gin Web Framework](https://chenyitian.gitbooks.io/gin-web-framework/content/)
 * [Go 101](https://go101.org/article/101.html) - [@TapirLiu](https://twitter.com/TapirLiu)
 * [Go by Example](https://gobyexample.com)
@@ -826,24 +826,24 @@ Books on general-purpose programming that don't focus on a specific language are
 * [How To Code in Go](https://www.digitalocean.com/community/books/how-to-code-in-go-ebook) - Mark Bates, Cory Lanou, Timothy J. Raymond (PDF, EPUB)
 * [Learn Go in Y minutes](https://learnxinyminutes.com/docs/go/)
 * [Learn Go with Tests](https://quii.gitbook.io/learn-go-with-tests/) - Chris James
-* [Learning Go](https://miek.nl/go/)
-* [Let's learn Go!](http://go-book.readthedocs.io/en/latest/)
+* [Learning Go](https://miek.nl/go/) (CC BY-NC-SA)
+* [Let's learn Go!](http://go-book.readthedocs.io/en/latest/) (CC BY-NC-SA)
 * [Practical Cryptography With Go](https://leanpub.com/gocrypto/read) - Kyle Isom
 * [Practical Go Lessons](https://www.practical-go-lessons.com) - Maximilien Andile
 * [Practical Go: Real world advice for writing maintainable Go programs](https://dave.cheney.net/practical-go/presentations/qcon-china.html) - Dave Cheney (HTML)
 * [Production Go](https://leanpub.com/productiongo/read) - Herman Schaaf and Shawn Smith (EPUB, HTML, PDF) (:construction: *in process*) *(Leanpub account or valid email requested for EPUB or PDF)*
 * [The Go Tutorial](http://tour.golang.org)
-* [The Little Go Book](https://github.com/karlseguin/the-little-go-book) - Karl Seguin ([PDF](https://www.openmymind.net/assets/go/go.pdf), [ePUB](https://www.openmymind.net/assets/go/go.epub))
-* [Web apps in Go, the anti textbook](https://github.com/thewhitetulip/web-dev-golang-anti-textbook/)
+* [The Little Go Book](https://github.com/karlseguin/the-little-go-book) - Karl Seguin ([PDF](https://www.openmymind.net/assets/go/go.pdf), [ePUB](https://www.openmymind.net/assets/go/go.epub)) (CC BY-NC-SA)
+* [Web apps in Go, the anti textbook](https://github.com/thewhitetulip/web-dev-golang-anti-textbook/) (CC BY-SA)
 
 
 ### Graphs
 
 #### GraphQL
 
-* [Fullstack GraphQL](https://github.com/GraphQLCollege/fullstack-graphql)
+* [Fullstack GraphQL](https://github.com/GraphQLCollege/fullstack-graphql) (CC BY-NC-SA)
 * [GraphQL or Bust](https://nordicapis.com/wp-content/uploads/GraphQL-or-Bust-v2.2.pdf) - Nordic APIs (PDF)
-* [Learning graphqL](https://riptutorial.com/Download/graphql.pdf) - Compiled from StackOverflow Documentation (PDF)
+* [Learning graphqL](https://riptutorial.com/Download/graphql.pdf) - Compiled from StackOverflow Documentation (PDF)  (CC BY-SA)
 
 
 #### Gremlin
@@ -866,7 +866,7 @@ Books on general-purpose programming that don't focus on a specific language are
 
 * [Building Java Projects with Gradle](http://spring.io/guides/gs/gradle/)
 * [Gradle Succinctly](https://www.syncfusion.com/ebooks/gradle_succinctly) - José Roberto Olivas Mendoza
-* [Gradle User Guide](https://docs.gradle.org/current/userguide/userguide.html) - Hans Dockter, Adam Murdoch ([PDF](https://docs.gradle.org/current/userguide/userguide.pdf))
+* [Gradle User Guide](https://docs.gradle.org/current/userguide/userguide.html) - Hans Dockter, Adam Murdoch ([PDF](https://docs.gradle.org/current/userguide/userguide.pdf)) (CC BY-NC-SA)
 
 
 #### Grails
@@ -892,7 +892,7 @@ Books on general-purpose programming that don't focus on a specific language are
 * [Cloudera Impala](https://docs.cloudera.com/documentation/enterprise/latest/PDF/cloudera-impala.pdf) - John Russel (PDF)
 * [Data-Intensive Text Processing with MapReduce](http://lintool.github.io/MapReduceAlgorithms/MapReduce-book-final.pdf) (Jimmy Lin and Chris Dyer) (PDF)
 * [Hadoop for Windows Succinctly](https://www.syncfusion.com/ebooks/hadoop-for-windows-succinctly) - Dave Vickers
-* [Hadoop Illuminated](http://hadoopilluminated.com/index.html) - Mark Kerzner, Sujee Maniyam
+* [Hadoop Illuminated](http://hadoopilluminated.com/index.html) - Mark Kerzner, Sujee Maniyam (CC BY-NC-SA)
 
 
 ### Haskell