Prevent 404s in README.md links

Fix links to ensure that they don't cause 404 errors when published to
Github Pages.

Fixes gh-304

spring-boot-tools/spring-boot-gradle-plugin/README.md

@@ -141,8 +141,8 @@ The following configuration options are available:
 
 ## Further Reading
 For more information on how Spring Boot Loader archives work, take a look at the
-[spring-boot-loader](../spring-boot-loader) module. If you prefer using Maven to
-build your projects we have a [spring-boot-maven-plugin](../spring-boot-maven-plugin).
+[spring-boot-loader](../spring-boot-loader/README.md) module. If you prefer using Maven to
+build your projects we have a [spring-boot-maven-plugin](../spring-boot-maven-plugin/README.md).
 
 ### Understanding how Boot Gradle Plugin Works
 When `spring-boot` is applied to your Gradle project a default task

spring-boot-tools/spring-boot-loader-tools/README.md

 # Spring Boot - Loader Tools
 The Spring Boot Loader Tools module provides support utilities to help when creating
-[Spring Boot Loader](../spring-boot-loader) compatible archives. This module is
+[Spring Boot Loader](../spring-boot-loader/README.md) compatible archives. This module is
 used by the various build system plugins that we provide.
 
 > **Note:** The quickest way to build a compatible archive is to use the
-> [spring-boot-maven-plugin](../spring-boot-maven-plugin) or
-> [spring-boot-gradle-plugin](../spring-boot-gradle-plugin).
+> [spring-boot-maven-plugin](../spring-boot-maven-plugin/README.md) or
+> [spring-boot-gradle-plugin](../spring-boot-gradle-plugin/README.md).
 
 ## Repackaging archives
 To repackage an existing archive so that it becomes a self-contained executable archive
@@ -47,6 +47,6 @@ repackager.repackage(new Libraries() {
 
 ## Further Reading
 For more information on how Spring Boot Loader archives work take a look at the
-[spring-boot-loader](../spring-boot-loader) module. If you want to see how we use this
-library the [Maven](../spring-boot-maven-plugin) and
-[Gradle](../spring-boot-gradle-plugin) plugins are good place to start.
+[spring-boot-loader](../spring-boot-loader/README.md) module. If you want to see how we use this
+library the [Maven](../spring-boot-maven-plugin/README.md) and
+[Gradle](../spring-boot-gradle-plugin/README.md) plugins are good place to start.

spring-boot-tools/spring-boot-loader/README.md

@@ -200,7 +200,8 @@ The `ZipEntry` for a nested jar must be saved using the `ZipEntry.STORED` method
 is required so that we can seek directly to individual content within the nested jar.
 The content of the nested jar file itself can still be compressed, as can any other
 entries in the outer jar. You can use the Spring Boot
-[Maven](../spring-boot-maven-plugin) or [Gradle](../spring-boot-gradle-plugin) plugins
+[Maven](../spring-boot-maven-plugin/README.md) or
+[Gradle](../spring-boot-gradle-plugin/README.md) plugins
 to ensure that your archives are written correctly.
 
 ### System ClassLoader
@@ -221,7 +222,7 @@ alternatives could be considered:
 ## Further Reading
 For more information about any of the classes or interfaces discussed in the document
 please refer to the project Javadoc. If you need to build a compatible archives see the
-[spring-boot-maven-plugin](../spring-boot-maven-plugin) or
-[spring-boot-gradle-plugin](../spring-boot-gradle-plugin). If you are not using Maven
-or Gradle [spring-boot-loader-tools](../spring-boot-loader-tools) provides some useful
-utilities to rewite existing zip files.
+[spring-boot-maven-plugin](../spring-boot-maven-plugin/README.md) or
+[spring-boot-gradle-plugin](../spring-boot-gradle-plugin/README.md). If you are not using
+Maven or Gradle [spring-boot-loader-tools](../spring-boot-loader-tools/README.md) provides
+some useful utilities to rewite existing zip files.

spring-boot-tools/spring-boot-maven-plugin/README.md

@@ -181,5 +181,5 @@ The following configuration options are available for the `spring-boot:run` goal
 
 ## Further Reading
 For more information on how Spring Boot Loader archives work, take a look at the
-[spring-boot-loader](../spring-boot-loader) module. If you prefer using Gradle to
-build your projects we have a [spring-boot-gradle-plugin](../spring-boot-gradle-plugin).
+[spring-boot-loader](../spring-boot-loader/README.md) module. If you prefer using Gradle to
+build your projects we have a [spring-boot-gradle-plugin](../spring-boot-gradle-plugin/README.md).