refactor: update server documentation

docs/metamodel_database.md

@@ -2,16 +2,16 @@
 
 ## Introduction
 
-To run ANIS need at least two databases: 
+To run, ANIS need at least two databases:
 
- - One database to store the configuration (`metamodel database`)
- - At least one database containing datasets
+ - One database to store the configuration (so called *metamodel database*)
+ - At least one database containing observation datasets (the *scientific database* or *business database*)
 
-Here we will explain how the metamodel database works. 
+Here we will explain how the **metamodel database** works.
 
-## Purpose of the database
+## Purpose of the metamodel database
 
-ANIS needs a database to store all the configuration : 
+ANIS needs a database to store all the configuration for:
 
  - The available business database(s) that should contains the shared datasets.
  - The different scientific projects.
@@ -24,9 +24,9 @@ ANIS needs a database to store all the configuration :
 
 ## Settings
 
-By default server container is configured to connect to a PostgreSQL database created during the first launch of docker-compose.
-The docker compose integrates a PostgreSQL database server named `db`. 
-You can find the `docker-compose.yml` file at the root of the anis-server project.
+By default, the `server` docker container is configured to connect to a PostgreSQL database created during the first launch of docker-compose.
+The docker compose integrates a [PostgreSQL](https://www.postgresql.org/) database server named `db`.
+You can find the `docker-compose.yml` file at the root of the `anis` project.
 
 The database settings connection are given in the environment variables of the `server` container.
 
@@ -42,11 +42,11 @@ Here is the list of server container configuration concerning the metamodel data
 - `DATABASE_CO_USER`: User name used to connect to the server metamodel database
 - `DATABASE_CO_PASSWORD`: Password used to connect to the server metamodel database
 
-You are free to change this configuration to connect to another database.
+You are free to change this configuration to connect to another metamodel database.
 
 ## Doctrine entities
 
-ANIS server uses a tool called doctrine to generate the database from the code. 
+ANIS server uses a tool called **doctrine** to generate the database from the code.
 You can find more information on the official website: [https://www.doctrine-project.org](https://www.doctrine-project.org).
 
 Anis server stores the different doctrine entities in the `server/src/Entity` folder and each file corresponds to a table in the metamodel database.
@@ -59,10 +59,10 @@ But be careful for each change you will have to re-generate the database and the
 ## Doctrine command-line tool
 
 You can use the doctrine command-line tool to perform most of the operations.
-To run the tool ANIS must be started.
+To run the tool, ANIS must be started.
 
-You must be at the root of the ANIS directory.
-And you can then enter into the server container by typing the following command:
+You must be at the root of the ANIS directory.  
+You can then enter into the server container by typing the following command:
 
 ```bash
 $ make shell_server