Add page about gradle setup

This new page is part of the basics section of the site.

basics/gradle.md

@@ -0,0 +1,71 @@
+---
+layout: content
+title: Gradle Integration
+author: wolfram
+as_version: 3.0
+cl_version: 1.0.2 or 1.1.0-beta5
+order: 6
+---
+
+### Top level build configuration
+You can add ConstraintLayout as you do with other dependencies: By adding it to your gradle `build.xml` file.
+
+Since ConstaintLayout is part of the Support Library family provided by Google, you have to use the [Google Maven repository](https://developer.android.com/studio/build/dependencies.html#google-maven).
+
+Most likely your project is using other parts of the Support Library family anyway, but to be sure, here's how to configure your top level build file to use the Google repository:
+
+```gradle
+buildscript {
+  repositories {
+    google()
+    jcenter()
+  }
+
+  dependencies {
+    classpath 'com.android.tools.build:gradle:3.0.1'
+  }
+}
+
+allprojects {
+  repositories {
+    google()
+    jcenter()
+  }
+}
+```
+
+
+### Module specific configuration
+With this configuration in place, you simply add the version of ConstraintLayout you want to the module specific gradle file (usually within the `app` module):
+
+```gradle
+dependencies {
+  // other libs...
+  implementation 'com.android.support.constraint:constraint-layout:1.1.0-beta5'
+  // other libs...
+}
+```
+
+
+### Versions
+Currently there are two versions available:
+* 1.0.2 - The stable version of the 1.0 release
+* 1.1.0-beta5 - The beta version of the upcoming 1.1 release
+
+All versions are listed on Google's [maven repository](https://dl.google.com/dl/android/maven2/com/android/support/constraint/group-index.xml).
+
+Features of the 1.1 branch that are missing in the 1.0 release:
+* [Barriers](barriers.html)
+* [Placeholders](https://developer.android.com/reference/android/support/constraint/Placeholder.html)
+* [Groups](https://developer.android.com/reference/android/support/constraint/Group.html)
+* [Circular positioning](https://developer.android.com/reference/android/support/constraint/ConstraintLayout.html#CircularPositioning)
+* Percent dimensions
+
+
+### Android Studio's Layout Editor
+Newer features of the ConstraintLayout are best supported in newer versions of Android Studio. While the 3.0.x versions are stable, they might not support all features of the latest betas. On the other hand the 3.1 and 3.2 versions are in active development. They are bound to contain bugs and might not properly support all of the older features.
+
+If you use XML anyway, the specific version of Android Studio is of less importance.
+
+
+

contributors/wolfram.md

@@ -0,0 +1,16 @@
+---
+forename: Wolfram
+surname: Rittmeyer
+admin: true
+twitter: RittmeyerW
+plus: WolframRittmeyer
+github: writtmeyer
+web: https://www.grokkingandroid.com/
+layout: contributor
+photo: photos/wolfram.jpg
+---
+Wolfram is an Android developer since 2012. He’s very active in the Android community, likes to speak at devfests and conferences and is co-organizer of the [GDG, Düsseldorf](https://www.meetup.com/Google-Developer-Group-Dusseldorf/).
+
+As a family guy Wolfram is a proud father of his two sons Linus and Niklas. Luckily they are also a nice source of inspiration when it comes to new ideas for tech use :-)
+
+And: Wolfram spent way too many years with Java (starting with 1.1) - until he happily switched to Kotlin.