Add documentation on how to run examples (#1125)

Add documentation on how to run examples

Resolves: #1122

---------

Co-authored-by: Christian Legnitto <LegNeato@users.noreply.github.com>

examples/README.md

@@ -0,0 +1,56 @@
+# Juniper Examples
+
+This directory contains examples of how to use Juniper.
+
+## How to run
+
+To run an example, you need to have a working Rust toolchain installed. You can
+get it from [rustup](https://rustup.rs/).
+
+Then, you can run the example using its workspace:
+
+```bash
+cargo run --example <example_name>
+```
+
+Where `<example_name>` is one of the following workspace members:
+
+```
+actix_server
+hyper_server
+iron_server
+rocket_server
+warp_server
+```
+
+e.g. to run the `actix_server` example:
+
+```bash
+cargo run --example actix_server
+```
+
+You can also run an example directly from an `examples` workspace directory. To
+run the `actix_server` example:
+
+```bash
+cd examples/actix_subscriptions
+cargo run
+     Finished dev [unoptimized + debuginfo] target(s) in 0.13s
+     Running `/path/to/repo/juniper/target/debug/example_actix_subscriptions`
+[2022-11-20T07:46:08Z INFO  actix_server::builder] Starting 10 workers
+[2022-11-20T07:46:08Z INFO  actix_server::server] Actix runtime found; starting in Actix runtime
+```
+
+Note if you want to run the code within your own project, you need to change
+the relative paths in `Cargo.toml`, e.g:
+
+```toml
+juniper_graphql_ws = { path = "../../juniper_graphql_ws" }
+```
+
+to:
+
+```toml
+juniper_graphql_ws = "0.3.0"
+```
+