add instance health check endpoint

Author: rdubrock

health.go

@@ -0,0 +1,18 @@
+package gapi
+
+type HealthResponse struct {
+	Code     string `json:"code,omitempty"`
+	Message  string `json:"message,omitempty"`
+	Commit   string `json:"commit,omitempty"`
+	Database string `json:"database,omitempty"`
+	Version  string `json:"version,omitempty"`
+}
+
+func (c *Client) Health() (HealthResponse, error) {
+	health := HealthResponse{}
+	err := c.request("GET", "/api/health", nil, nil, &health)
+	if err != nil {
+		return health, err
+	}
+	return health, nil
+}