test-in-docker: quickly test frameworks in docker

This adds `./test-in-docker` for quickly playing with various frameworks.

All the containers are based off Ubuntu 14.04 which has ZSH 5.0.2.

Thanks to @dritter for figuring out all the framework installation
methods.

docker/omz/Dockerfile

@@ -0,0 +1,7 @@
+FROM p9k:base
+
+COPY docker/omz/install.zsh /tmp/
+RUN zsh /tmp/install.zsh
+
+COPY docker/omz/zshrc .zshrc
+COPY ./ p9k/

docker/omz/install.zsh

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+sh -c "$(curl -fsSL https://raw.githubusercontent.com/robbyrussell/oh-my-zsh/master/tools/install.sh)"
+
+mkdir -p ~/.oh-my-zsh/custom/themes
+ln -nsf ~/p9k/ ~/.oh-my-zsh/custom/themes/powerlevel9k

docker/omz/zshrc

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+export ZSH=$HOME/.oh-my-zsh
+ZSH_THEME="powerlevel9k/powerlevel9k"
+plugins=(git rake ruby)
+
+source $ZSH/oh-my-zsh.sh