Add instructions for running nexus locally.

DEVELOPERS.md

@@ -1,6 +1,29 @@
 ## Developer instructions
 
-* How to release a new version
+### Testing a release locally
+Run nexus locally (assuming you have docker running locally):
+
+```bash
+docker run -d -p 8081:8081 --name nexus sonatype/nexus
+```
+
+Configure the `distributionManagement` section in the root `pom.xml` to point to the repo on localhost.
+
+Add/update your `~/.m2/settings.xml` with the following config block:
+
+```xml
+<settings>
+  <servers>
+    <server>
+      <id>nexus-local</id>
+      <username>admin</username>
+      <password>admin123</password>
+    </server>
+  </servers>
+</settings>
+```
+
+Perform the release process as described below.
 
 
 ### How to release a new version

pom.xml

@@ -51,11 +51,11 @@
 
     <distributionManagement>
         <snapshotRepository>
-            <id>nexus</id>
+            <id>nexus-local</id>
             <url>http://localhost:8081/nexus/content/repositories/snapshots</url>
         </snapshotRepository>
         <repository>
-            <id>nexus</id>
+            <id>nexus-local</id>
             <url>http://localhost:8081/nexus/content/repositories/snapshots</url>
         </repository>
         <!--<snapshotRepository>-->