Add support for CircleCI (#272)

* Add support for CircleCI

* Update README.md

README.md

@@ -107,6 +107,26 @@ Travis build and you should see coverage reports appear on [coveralls][].
 2) Job done! Commit these changes to kick off your GitHub Actions
 build and you should see coverage reports appear on [coveralls][].
 
+## CircleCI Integration
+
+Enable CircleCI support in your `build.sbt`:
+
+```scala
+import org.scoverage.coveralls.Imports.CoverallsKeys._
+import org.scoverage.coveralls.CircleCI
+
+coverallsService := Some(CircleCI)
+```
+
+Add the following step to your `config.yml` right after your test step:
+
+```yaml
+- run:
+    name: Generate and upload coverage report
+    when: always
+    command: sbt ";coverageReport ;coverageAggregate ;coveralls"
+```
+
 ## Manual Usage
 
 1)  Get the repo token for your repo from [coveralls][].

src/main/scala/org/scoverage/coveralls/CIService.scala

@@ -94,3 +94,10 @@ case object GitHubActions extends CIService {
     }
   }
 }
+
+object CircleCI extends CIService {
+  def name: String = "circleci"
+  def jobId: Option[String] = sys.env.get("CIRCLE_BUILD_NUM")
+  def pullRequest: Option[String] = sys.env.get("CIRCLE_PULL_REQUEST").map(_.split("/").last)
+  def currentBranch: Option[String] = sys.env.get("CIRCLE_BRANCH")
+}