Add usage instructions to top-level README

Also delete redundant `README` from `server` directory.

assessments/semiprimes/README.md

@@ -28,3 +28,17 @@ numbers *Semiprimes*.
   return the answer for all.
 - Considering this module will be used by a long running service, could you
   optimize it to give answers faster?
+
+## Usage
+
+To run the application you'll need to have `elixir` installed. Assuming `elixir`
+is already installed, consult the following steps to start the application:
+
+```shell
+$ cd server
+$ mix deps.get
+$ iex -S mix
+```
+
+Now open a web browser and visit `http://localhost:8080`!
+

assessments/semiprimes/server/README.md

@@ -1,21 +0,0 @@
-# Server
-
-**TODO: Add description**
-
-## Installation
-
-If [available in Hex](https://hex.pm/docs/publish), the package can be installed
-by adding `server` to your list of dependencies in `mix.exs`:
-
-```elixir
-def deps do
-  [
-    {:server, "~> 0.1.0"}
-  ]
-end
-```
-
-Documentation can be generated with [ExDoc](https://github.com/elixir-lang/ex_doc)
-and published on [HexDocs](https://hexdocs.pm). Once published, the docs can
-be found at [https://hexdocs.pm/server](https://hexdocs.pm/server).
-