README: Update to add IntelliJ pub instructions (#182)

diff --git a/README.md b/README.md
index 2d70773..3daa618 100644
--- a/README.md
+++ b/README.md
@@ -22,6 +22,12 @@
 
 2.  Install it
 
+    If you're using IntelliJ, choose:
+
+    ```
+    Control + Shift + A > Pub: Get Dependencies
+    ```
+
     If you're using the Dart Editor, choose:
 
     ```