Refactor to fix R CMD check issues

.Rbuildignore

@@ -1,2 +1,6 @@
 ^.*\.Rproj$
 ^\.Rproj\.user$
+^LICENSE\.md$
+^\.github$
+^attic$
+^README\.Rmd$

.github/.gitignore

@@ -0,0 +1 @@
+*.html

.github/workflows/R-CMD-check.yaml

@@ -0,0 +1,51 @@
+# Workflow derived from https://github.com/r-lib/actions/tree/v2/examples
+# Need help debugging build failures? Start at https://github.com/r-lib/actions#where-to-find-help
+on:
+  push:
+    branches: [main, master]
+  pull_request:
+
+name: R-CMD-check.yaml
+
+permissions: read-all
+
+jobs:
+  R-CMD-check:
+    runs-on: ${{ matrix.config.os }}
+
+    name: ${{ matrix.config.os }} (${{ matrix.config.r }})
+
+    strategy:
+      fail-fast: false
+      matrix:
+        config:
+          - {os: macos-latest,   r: 'release'}
+          - {os: windows-latest, r: 'release'}
+          - {os: ubuntu-latest,   r: 'devel', http-user-agent: 'release'}
+          - {os: ubuntu-latest,   r: 'release'}
+          - {os: ubuntu-latest,   r: 'oldrel-1'}
+
+    env:
+      GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
+      R_KEEP_PKG_SOURCE: yes
+
+    steps:
+      - uses: actions/checkout@v4
+
+      - uses: r-lib/actions/setup-pandoc@v2
+
+      - uses: r-lib/actions/setup-r@v2
+        with:
+          r-version: ${{ matrix.config.r }}
+          http-user-agent: ${{ matrix.config.http-user-agent }}
+          use-public-rspm: true
+
+      - uses: r-lib/actions/setup-r-dependencies@v2
+        with:
+          extra-packages: any::rcmdcheck
+          needs: check
+
+      - uses: r-lib/actions/check-r-package@v2
+        with:
+          upload-snapshots: true
+          build_args: 'c("--no-manual","--compact-vignettes=gs+qpdf")'

DESCRIPTION

@@ -1,26 +1,25 @@
-Package: expard
 Type: Package
-Title: Drug EXPosures and ADRs 
+Package: expard
+Title: Drug 'EXPosures' and 'ADRs'
 Version: 1.0.0
-Author: Louis Dijkstra
-Maintainer: Louis Dijkstra <louisdijkstra@gmail.com>
-Description: An R package for fitting complex drug exposure 
-             and adverse drug reaction (ADR) relationships
-Depends:
-	  R (>= 3.4.3),
-	  ggplot2,
-	  crayon,
-	  dplyr, 
-	  Matrix,
-	  parallel
-License: GPL-3
-Encoding: UTF-8
-LazyData: true
-RoxygenNote: 7.2.3
-Roxygen: list(markdown = TRUE)
+Authors@R: 
+    person("Louis", "Dijkstra", , "louisdijkstra@gmail.com", role = c("aut", "cre"))
+Description: An R package for fitting complex drug exposure and adverse
+    drug reaction ('ADR') relationships. It can additionally be used to
+    simulate electronic healthcare record ('EHR') data of patients
+    observed across multiple timepoints.
+License: GPL (>= 3)
 URL: https://github.com/bips-hb/expard
 BugReports: https://github.com/bips-hb/expard/issues
-Suggests: 
-    knitr,
-    rmarkdown
-VignetteBuilder: knitr
+Imports:
+    crayon,
+    dplyr,
+    ggplot2,
+    Matrix,
+    parallel,
+    rlang,
+    stats,
+    utils
+Encoding: UTF-8
+Roxygen: list(markdown = TRUE)
+RoxygenNote: 7.3.2