Update README with docker steps and add gitignore.

Author: carlosperate

.gitignore

@@ -0,0 +1,33 @@
+###########
+# Project #
+###########
+# Nothing yet
+
+######################
+# OS generated files #
+######################
+# macoOS
+.DS_Store
+.DS_Store?
+.AppleDouble
+.LSOverride
+._*
+.Spotlight-V100
+.Trashes
+Icon?
+
+# Windows
+Thumbs.db
+ehthumbs.db
+ehthumbs_vista.db
+*.stackdump
+[Dd]esktop.ini
+$RECYCLE.BIN/
+*.lnk
+
+# Linux
+*~
+.fuse_hidden*
+.directory
+.Trash-*
+.nfs*

README.md

@@ -1,2 +1,29 @@
-# docker-microbit-toolchain
-Docker image with the micro:bit toolchain
+# Docker micro:bit Toolchain
+
+Docker image with the micro:bit toolchain.
+
+## Instructions
+
+### Build docker image
+
+Build the docker image:
+
+```
+docker build -t "ubit-toolchain-img" .
+```
+
+For better traceability it's good to save the build output, so preferably do:
+
+### Run a bash session
+
+Run a bash session (launches a new container) inside an existing docker image:
+
+```
+docker run --name ubit-toolchain-container -it --entrypoint /bin/bash ubit-toolchain-img
+```
+
+### Copy files from docker to host
+
+```
+docker cp ubit-toolchain-container:/home/artefacts .
+```