DATAREDIS-832 - Added a cover page for epub output.

I added a cover page for the epub output, now that the Spring data reference guides will
have epub output (through a commit against spring-data-build).

Original pull request: #339.

src/main/asciidoc/index.adoc

@@ -4,6 +4,14 @@ Costin Leau, Jennifer Hickey, Christoph Strobl, Thomas Darimont, Mark Paluch, Ja
 :revdate: {localdate}
 :toc:
 :toc-placement!:
+:linkcss:
+:doctype: book
+:docinfo: shared
+:toclevels: 4
+:source-highlighter: prettify
+:icons: font
+:imagesdir: images
+ifdef::backend-epub3[:front-cover-image: image:epub-cover.png[Front Cover,1050,1600]]
 :spring-data-commons-include: ../../../../spring-data-commons/src/main/asciidoc
 :spring-data-commons-docs: https://raw.githubusercontent.com/spring-projects/spring-data-commons/master/src/main/asciidoc
 
@@ -15,50 +23,32 @@ toc::[]
 
 include::preface.adoc[]
 
-:leveloffset: +1
-include::new-features.adoc[]
-
-:leveloffset: -1
+include::new-features.adoc[leveloffset=+1]
 
 [[introduction]]
 = Introduction
 
-:leveloffset: +1
-include::introduction/introduction.adoc[]
 
-include::introduction/why-sdr.adoc[]
-
-include::introduction/requirements.adoc[]
-
-include::introduction/getting-started.adoc[]
-
-:leveloffset: -1
+include::introduction/introduction.adoc[leveloffset=+1]
+include::introduction/why-sdr.adoc[leveloffset=+1]
+include::introduction/requirements.adoc[leveloffset=+1]
+include::introduction/getting-started.adoc[leveloffset=+1]
 
 [[reference]]
 = Reference Documentation
 
-:leveloffset: +1
-include::reference/introduction.adoc[]
 
-include::reference/redis.adoc[]
-
-include::reference/reactive-redis.adoc[]
-
-include::reference/redis-cluster.adoc[]
-
-include::reference/redis-repositories.adoc[]
-
-:leveloffset: -1
+include::reference/introduction.adoc[leveloffset=+1]
+include::reference/redis.adoc[leveloffset=+1]
+include::reference/reactive-redis.adoc[leveloffset=+1]
+include::reference/redis-cluster.adoc[leveloffset=+1]
+include::reference/redis-repositories.adoc[leveloffset=+1]
 
 [[appendixes]]
 = Appendixes
 
 :numbered!:
-:leveloffset: +1
-include::appendix/introduction.adoc[]
 
-include::appendix/appendix-schema.adoc[]
-
-include::appendix/appendix-command-reference.adoc[]
-
-:leveloffset: -1
+include::appendix/introduction.adoc[leveloffset=+1]
+include::appendix/appendix-schema.adoc[leveloffset=+1]
+include::appendix/appendix-command-reference.adoc[leveloffset=+1]