readme: add animation

This commit adds the sample animation and expands the readme to contain
a guide of how to install and use confex.

README.md

@@ -1,2 +1,56 @@
 # confex
-confex helps you explore configuration files
+
+[![Go Report Card](https://goreportcard.com/badge/github.com/oncilla/confex)](https://goreportcard.com/report/github.com/oncilla/confex)
+
+confex helps you explore configuration files. It currently supports yaml, json,
+and toml configurations.
+
+## Installation
+
+    go get github.com/oncilla/confex@latest
+
+
+In case you see the following error:
+
+    go: cannot use path@version syntax in GOPATH mode
+
+run:
+
+    GO111MODULE=on go get github.com/oncilla/confex@latest
+
+
+## Usage
+
+Supply any yml, json, or toml file to explore it.
+
+    confex config.json
+
+confex also supports piped input.
+
+    echo $( curl http://headers.jsontest.com/ ) | confex
+
+## Key bindings
+
+    Basic navigation
+    --------------------------------------
+     k,  <UP>       Move up
+     j,  <Down>     Move down
+     gg, <Home>     Go to top
+     G,  <End>      Go to end
+     e,  <Enter>    Toggle expand
+     E              Expand all
+     C              Collapse all
+
+     h              Show help message
+     q, <ctrl-c>    Quit
+
+
+    Extended navigation
+    --------------------------------------
+     <ctrl-d>       Half page down outline
+     <ctrl-u>       Half page up outline
+     <ctrl-f>       Page down outline
+     <ctrl-b>       Page up outline
+
+
+![](sample/sample.gif)