Update graphql-client-cli's README.md

Author: h-michael

graphql_client_cli/README.md

@@ -1,3 +1,61 @@
 # GraphQL client CLI
 
 This is still a WIP, the main use for it now is to download the `schema.json` from a GraphQL endpoint, which you can also do with [apollo-codegen](https://github.com/apollographql/apollo-cli).
+
+## Install
+
+```
+cargo install graphql-client-cli
+```
+
+## introsect schema
+
+```
+USAGE:
+    graphql-client introspect-schema [OPTIONS] <schema_location>
+
+FLAGS:
+    -h, --help       Prints help information
+    -V, --version    Prints version information
+
+OPTIONS:
+        --authorization <authorization>
+        --output <output>                  Where to write the JSON for the introspected schema.
+
+ARGS:
+    <schema_location>    The URL of a GraphQL endpoint to introspect.
+```
+
+## generate client code
+
+```
+USAGE:
+    graphql-client generate [FLAGS] [OPTIONS] <query_path> <schema_path> <module_name> <output>
+
+FLAGS:
+    -h, --help             Prints help information
+        --no-formatting    If you don't want to execute rustfmt to generated code, set this option. Default value is
+                           false. Formating feature is disabled as default installation.
+    -V, --version          Prints version information
+
+OPTIONS:
+    -a, --additional-derives <additional_derives>
+            Additional derives that will be added to the generated structs and enums for the response and the variables.
+            --additional-derives='Serialize,PartialEq'
+    -d, --deprecation-strategy <deprecation_strategy>
+            You can choose deprecation strategy from allow, deny, or warn. Default value is warn.
+
+    -o, --selected-operation <selected_operation>
+            Name of target query. If you don't set this parameter, cli generate all queries in query file.
+
+
+ARGS:
+    <query_path>     Path to graphql query file.
+    <schema_path>    Path to graphql schema file.
+    <module_name>    Name of module.
+    <output>         Path you want to output to.
+```
+
+If you want to use formatting feature, you should install like this.
+
+`cargo install graphql-client-cli --features rustfmt`