Update README with install and usage info.

README.md

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 # Gabi CLI
+
+This is a CLI written for the GABI service. For details about GABI, [look here](https://github.com/app-sre/gabi).
+
+To run this CLI you will need a current session into the Openshift cluster you would like to query. Please make sure you are logged into the cluster via `oc login` before running Gabi CLI.
+
+You also need to be connected to the Openshift project running the database container that you wish to query. You can do so by running `oc project <projectname>`.
+
+## Installation
+
+You can download and install the latest release of the Gabi CLI with this command:  
+`go install github.com/vkrizan/gabi-cli.git@latest`
+
+After which you should be able to run it with `gabi-cli`.
+
+If you receive a `command not found` error, make sure that your go bin directory has been added to your path. For information on what your go bin directory is, run `go help install`.
+
+## Usage
+```
+Usage of gabi-cli:
+  -h    Shows help
+  -kubeconfig string
+        (optional) absolute path to the kubeconfig file (default "~/.kube/config")
+  -n string
+        Namespace (defaults to current context)
+  -q    Suppress logging messages
+```
+
+If your system is correctly configured (logged into Openshift and a GABI compliant project selected), then running `gabi-cli` should report the namespace, cluster, and GABI url you have accessed and drop you into a database query prompt.
+
+In this prompt you may interact with the database via SQL query strings.
+
+Some examples:  
+`SELECT * FROM pg_catalog.pg_tables;` -> List all tables for a Postgres database  
+`SELECT COUNT(*) FROM <table>;` -> Count the number of rows in table \<table\>  
+`SELECT column_name, data_type FROM information_schema.columns WHERE table_name = '<table>';` -> List column names and types for \<table\> in a Postgres database.
+
+**NOTE:** Only query strings may be used. PSQL commands, such as `\d` and `\gdesc` will not work.
+
+You may scroll through the command history with the up and down arrow keys.
+
+`Ctrl + L` will clear the screen.
+
+`Ctrl + D` will quit the prompt and exit Gabi CLI.