Changes in this commit:
- Singularize all routes and components
- Separate different modules into their own source files
- Rename the API module to enrollment and add a more general API module
- Resources that are related to a route, are now under its scope. For
  example, the year range of the enrollment component is now under the
  route /v1/enrollment/year_range
- Implement a thenable function to execute the queries against the
  database to reduce the amount of duplicated code in the application. This
  approach also allows several concurrent queries to run concurrently in the
  same route.

Signed-off-by: João Victor Risso <jvtr12@c3sl.ufpr.br>

Signed-off-by: João Victor Risso <jvtr12@c3sl.ufpr.br>

Signed-off-by: João Victor Risso <jvtr12@c3sl.ufpr.br>

Major modifications:
- Source code is now in the src directory
- All source files were adapted to ECMAScript6
- Add Gulpfile and Babel to transcompile the project from ES6 to ES5 (until Node.js fully supports ES6)
	- By running gulp one generates the build directory with the files transcompiled, from which the API can be run
- Add ESLint to check for syntax errors and enforce code standards
	- Javascript coding standard currently adopted is AirBnB with 4 spaces
- Replace monetdb package with monetdb-pool, which allows for concurrent queries over a pool of connections while maintaining the same interface

TODO (in order of priority, from high to low):
- Add Gulp tasks to handle automatic building, tests and running the server in order to deprecate using npm
- Implement decorator to execute the SQL queries and reduce code duplication.
- Implement SQL query builder (e.g. squel.js) to erradicate the need for embedding SQL directly into the code (which is error-prone).
- Change enrollments route not to use route chaining in order to decide which SQL query is appropriate to respond the user's request.
- Implement decorator for API responses and also reduce code duplication.
- Split up tests into and add more test cases.

Signed-off-by: João Victor Risso <jvtr12@c3sl.ufpr.br>

Changelog:
- Add education level to all queries

- Add route '/education_level' to query the available education levels.
  The response is a set of pairs (id, education_level)

- Change var declarations to their respective const and let counterparts

- Fix wrong foreign key name in the aggregation by states. When a
  adm_dependency_id parameter was supplied, the query would fail.

Changes:
- Add error handling in the database query function. When a database error
occurs, it is logged in the server and a plain text response is returned to the
user.
- Implement the building of queries inside the API, which removes the
  need to have stored functions/procedures on the database, which is not
  flexible or efficient to maintain/extend.
- Use route chaining to determine which function will build the query
  that needs to be executed. The last function is the one that actually
  sends the query to the database and send the response.

Future Work:
- Instead of returning a plain text response, return a HTTP 501 status,
  which is currently not possible. When one attempts to send such status
  the framework throws an error that the headers were already sent for
  the current request.
- Chaining based on the route might not be the best solution here.

Tests



See merge request !6

Implement basic queries for enrollments

# Description

Implemented enrollments queries per:
- Region
- State
- City

The *census_year* parameter is *mandatory* and should be included in all requests.

The "/enrollments" route supports the following parameters

- aggregate: metric to aggregate, can be {state, region, city}. When no parameter is supplied or the parameter is not supported, the API assumes the whole country.
- id: record identifer of the metric to aggregate (e.g. one specific state or region), it only applies when the aggregate parameters is passed and is valid. Again, when no parameter is specified, the API assumes the whole range of values the metric can take (e.g. all states or all regions).
- adm_dependency_id: administrative dependency identifier, the possible values are shown in the Table 1.

- location_id: location identifier, its possible values are given in Table 2.

# Tables

*Table 1:* Administrative dependency table.

| adm_dependency_id | name           |
|---------------------------|---------------|
| 0                                          | All records  |
| 1                                          | Federal        |
| 2                                          | Estadual     |
| 3                                          | Municipal   |
| 4                                           | Privada       |

*Table 2:* Location table.

| location_id  | name            |
|----------------|---------------|
| 0                        | All records  |
| 1                        | Urbana        |
| 2                        | Rural            |

# Response Format

The API returns a JSON array with name "result" where every array has following attributes:
- name: Name of the metric (e.g. name of a state, city or region)
- total: Total number of enrollments for the selected metric and given parameters.

# Examples
Retrieve the number of enrollments of 2014 for the whole country:
> /api/v1/enrollments?census_year=2014

Retrieve the number of enrollments of 2013 for a given region:
> /api/v1/enrollments?census_year=2013&aggregate=region&id=1

Retrieve the number of enrollments of 2012 for all rural locations in the state of Paraná:
> /api/v1/enrollments?census_year=2012&aggregate=state&id=41&location_id=2

Retrieve the number of enrollments of 2012 for the North region:
> /api/v1/enrollments?census_year=2012&aggregate=region&id=1

See merge request !5

Signed-off-by: João Victor Tozatti Risso <jvtr12@c3sl.ufpr.br>

Signed-off-by: João Victor Tozatti Risso <jvtr12@c3sl.ufpr.br>

Tests



See merge request !3

Fixed XML output

Closes #6

See merge request !4

Closes #6

Signed-off-by: João Victor Tozatti Risso <jvtr12@c3sl.ufpr.br>

Signed-off-by: João Victor Tozatti Risso <jvtr12@c3sl.ufpr.br>

Conflicts:
	libs/routes/api.js

- Rename /matriculas to /enrollments
- Add initial support for parameters in the enrollments route

Conflicts:
	package.json