chore(sample): describe jspm forks, closes #172

sample/src/help/docs/app-developers-tutorials/next-actions.md

@@ -3,4 +3,42 @@
 ### 7. What you need to know
 <br>
 
-__To be written__ ...
+#### JSPM "forks"
+<br>
+
+JSPM allows for multiple versions of installed dependencies. When two dependencies
+import two different versions of the same library, JSPM may detect a conflict
+which it calls a "fork". In this case it issues a warning like this:
+
+```
+Installed Forks
+
+             github:systemjs/plugin-css 0.1.20 0.1.21
+```
+
+This example is taken from aurelia-skeleton-navigation 1.0.0-beta.1.2.2 (after installing the bridge)
+which has a dependency on `font-awesome@^4.5.0` - itself depending on `[email protected]`.
+Notice lack of the `^` indicator, meaning that JSPM will install **exactly this version**.
+
+When installing the bridge you install an indirect dependency of `[email protected]`
+which `Dogfalo/materialize` depends on.
+
+As the version numbers in both cases are static (no `^` indicator), both versions
+of `plugin-css` are installed, leading to a fork.
+
+There are two options to resolve this:
+* install with the `--lock` option
+* use `jspm resolve`
+
+##### Installing the bridge using `--lock`
+
+The `--lock` option keeps existing dependencies locked during a JSPM installation.
+So if you know the installation will introduce a fork and you want to keep
+the installed version of a library, use `jspm install --lock aurelia-materialize-bridge`.
+
+##### Using `jspm resolve`
+
+JSPM has a builtin command to change every used version of a dependency to the
+version you want.
+In the case above you'd issue `jspm resolve --only github:systemjs/[email protected]`.
+Please note that you *have to* give JSPM an exact package of the form `registry:pkg@version`.