Add installation instructions to module-info.java.

Change-Id: I45d8814d49ff33f865c23efddca7fea2ae8aaf2f
diff --git a/src/main/java/module-info.java b/src/main/java/module-info.java
index 4e358d2..0282ff8 100644
--- a/src/main/java/module-info.java
+++ b/src/main/java/module-info.java
@@ -2,8 +2,57 @@
  * Provides a parser for the <a href="https://docs.gtk.org/glib/struct.Variant.html">GVariant</a>
  * serialization format.
  *
+ * <ul>
+ *   <li><a href="#sect-overview">Overview</a>
+ *   <li><a href="#sect-installation">Installation</a>
+ * </ul>
+ *
+ * <h2 id="sect-overview">Overview</h2>
+ *
  * <p>The {@link eu.mulk.jgvariant.core} package contains the {@link eu.mulk.jgvariant.core.Decoder}
- * type, which forms the foundation of this library.
+ * type, which contains classes to parse and represent serialized <a
+ * href="https://docs.gtk.org/glib/struct.Variant.html">GVariant</a> values.
+ *
+ * <h2 id="sect-installation">Installation</h2>
+ *
+ * <ul>
+ *   <li><a href="#sect-installation-maven">Usage with Maven</a>
+ *   <li><a href="#sect-installation-gradle">Usage with Gradle</a>
+ * </ul>
+ *
+ * <h3 id="sect-installation-maven">Usage with Maven</h3>
+ *
+ * <pre>{@code
+ * <project>
+ *   ...
+ *
+ *   <dependencies>
+ *     ...
+ *
+ *     <dependency>
+ *       <groupId>eu.mulk.jgvariant</groupId>
+ *       <artifactId>jgvariant-core</artifactId>
+ *       <version>0.1.3</version>
+ *     </dependency>
+ *
+ *     ...
+ *   </dependencies>
+ *
+ *   ...
+ * </project>
+ * }</pre>
+ *
+ * <h3 id="sect-installation-gradle">Usage with Gradle</h3>
+ *
+ * <pre>{@code
+ * dependencies {
+ *   ...
+ *
+ *   implementation("eu.mulk.jgvariant:jgvariant-core:0.1.3")
+ *
+ *   ...
+ * }
+ * }</pre>
  */
 module eu.mulk.jgvariant.core {
   requires com.google.errorprone.annotations;