Restructure and add quickstart to docs

docs/cli/usage.mdx

@@ -0,0 +1,51 @@
+---
+title: "Usage"
+---
+
+Prerequisite: [Install the CLI](/cli/overview)
+
+## Log in to the Infisical CLI
+
+```bash
+infisical login
+```
+
+## Initialize Infisical for your project
+
+```bash
+# move to your project
+cd /path/to/project
+
+# initialize infisical
+infisical init
+```
+
+## Inject environment variables
+
+```bash
+# inject environment variables into app
+infisical run -- [your application start command]
+```
+
+Options you can specify:
+
+| Option        | Description                                                                                                 | Default value |
+| ------------- | ----------------------------------------------------------------------------------------------------------- | ------------- |
+| `--env`       | Used to set the environment that secrets are pulled from. Accepted values: `dev`, `staging`, `test`, `prod` | `dev`         |
+| `--projectId` | Used to link a local project to the platform (required only if injecting via the service token method)      | `None`        |
+
+## Examples:
+
+```bash
+# example with node
+infisical run -- node index.js
+
+# example with node (nodemon)
+infisical run -- nodemon index.js
+
+# example with node (nodemon) pulling in secrets from test environment
+infisical run --env=test -- nodemon index.js
+
+# example with flask
+infisical run -- flask run
+```